diff --git a/README.md b/README.md
index 2854b0b..2e1cb36 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,7 @@
 | /api/v1/transaction/verify       | completePurchase |
 | /api/v1/transaction/by/sessionId | purchaseInfo     |
 | /api/v1/card/info                | cardInfo         |
+| /api/v1/transaction/refund       | refund           |
 
 ## Install
 
@@ -35,6 +36,8 @@ The following gateways are provided by this package:
 
 * Przelewy24
 
+Reference official documentation https://developers.przelewy24.pl/index.php
+
 ## Example
 
 ```php
diff --git a/composer.json b/composer.json
index 9fc5e51..f6ced46 100644
--- a/composer.json
+++ b/composer.json
@@ -17,6 +17,10 @@
     {
       "name": "Piotr Synowiec",
       "email": "psynowiec@gmail.com"
+    },
+    {
+      "name": "Adam Migacz",
+      "email": "smigi1997@gmail.com"
     }
   ],
   "autoload": {
@@ -26,8 +30,9 @@
   },
   "require": {
     "omnipay/common": "^3",
+    "ext-json": "*",
     "ext-bcmath": "*",
-    "ext-json": "*"
+    "php": "^7.2|^8.0"
   },
   "require-dev": {
     "omnipay/tests": "^3",
diff --git a/ecs.php b/ecs.php
index 27b97c5..0d9592a 100644
--- a/ecs.php
+++ b/ecs.php
@@ -21,9 +21,9 @@
             'syntax' => 'short',
         ]]);
 
-     $ecsConfig->import(SetList::SPACES);
-     $ecsConfig->import(SetList::ARRAY);
-     $ecsConfig->import(SetList::DOCBLOCK);
-     $ecsConfig->import(SetList::PSR_12);
-     $ecsConfig->import(SetList::CLEAN_CODE);
+    $ecsConfig->import(SetList::SPACES);
+    $ecsConfig->import(SetList::ARRAY);
+    $ecsConfig->import(SetList::DOCBLOCK);
+    $ecsConfig->import(SetList::PSR_12);
+    $ecsConfig->import(SetList::CLEAN_CODE);
 };
diff --git a/src/Gateway.php b/src/Gateway.php
index 1550911..6d7b103 100644
--- a/src/Gateway.php
+++ b/src/Gateway.php
@@ -11,6 +11,7 @@
 use Omnipay\Przelewy24\Message\MethodsRequest;
 use Omnipay\Przelewy24\Message\PurchaseInfoRequest;
 use Omnipay\Przelewy24\Message\PurchaseRequest;
+use Omnipay\Przelewy24\Message\RefundsRequest;
 use Omnipay\Przelewy24\Message\TestAccessRequest;
 
 class Gateway extends AbstractGateway
@@ -162,4 +163,13 @@ public function cardInfo(string $transactionId): CardInfoRequest
             'transactionId' => $transactionId,
         ]);
     }
+
+    /**
+     * @param string[] $options
+     * @return AbstractRequest|RefundsRequest
+     */
+    public function refund(array $options = []): RefundsRequest
+    {
+        return $this->createRequest(RefundsRequest::class, $options);
+    }
 }
diff --git a/src/Message/AbstractRequest.php b/src/Message/AbstractRequest.php
index 9acbca5..996ec7d 100644
--- a/src/Message/AbstractRequest.php
+++ b/src/Message/AbstractRequest.php
@@ -104,7 +104,7 @@ protected function sendRequest(string $method, string $endpoint, $data): Respons
                     base64_encode(sprintf('%s:%s', $this->getMerchantId(), $this->getReportKey()))
                 ),
             ],
-            empty($data) ? null : json_encode($data)
+            empty($data) ? null : json_encode($data, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES)
         );
     }
 
diff --git a/src/Message/AbstractResponse.php b/src/Message/AbstractResponse.php
index fc55dbd..0d65ea5 100644
--- a/src/Message/AbstractResponse.php
+++ b/src/Message/AbstractResponse.php
@@ -6,15 +6,10 @@
 
 use Omnipay\Common\Message\AbstractResponse as BaseAbstractResponse;
 use Omnipay\Common\Message\RequestInterface;
+use Symfony\Component\HttpFoundation\Response;
 
 abstract class AbstractResponse extends BaseAbstractResponse
 {
-    public const HTTP_OK = 200;
-
-    public const HTTP_BAD_REQUEST = 400;
-
-    public const HTTP_UNAUTHORIZED = 401;
-
     /**
      * @param string[] $data
      */
@@ -26,13 +21,16 @@ public function __construct(RequestInterface $request, $data)
     public function getCode(): int
     {
         if (isset($this->data['code'])) {
-            return $this->data['code'];
+            return (int) $this->data['code'];
         }
 
-        return self::HTTP_OK;
+        return Response::HTTP_OK;
     }
 
-    public function getMessage(): string
+    /**
+     * @return array|string|null
+     */
+    public function getMessage()
     {
         if (isset($this->data['error'])) {
             return $this->data['error'];
@@ -43,7 +41,9 @@ public function getMessage(): string
 
     public function isSuccessful(): bool
     {
-        return self::HTTP_OK === $this->getCode();
+        $code = $this->getCode();
+
+        return in_array($code, [Response::HTTP_CREATED, Response::HTTP_OK]);
     }
 
     protected function getAmountFromInternal(int $amount): string
diff --git a/src/Message/PurchaseInfoResponse.php b/src/Message/PurchaseInfoResponse.php
index 4c331d1..1168cbf 100644
--- a/src/Message/PurchaseInfoResponse.php
+++ b/src/Message/PurchaseInfoResponse.php
@@ -40,7 +40,7 @@ public function getCode(): int
             return $this->data['code'];
         }
 
-        return self::HTTP_OK;
+        return Response::HTTP_OK;
     }
 
     /**
diff --git a/src/Message/PurchaseRequest.php b/src/Message/PurchaseRequest.php
index 78c5e79..976ac9d 100644
--- a/src/Message/PurchaseRequest.php
+++ b/src/Message/PurchaseRequest.php
@@ -133,7 +133,7 @@ public function getShipping()
 
     public function setShipping($value): self
     {
-        return $this->setParameter('regulationAccept', $value);
+        return $this->setParameter('shipping', $value);
     }
 
     public function getTransactionLabel(): ?string
diff --git a/src/Message/RefundsRequest.php b/src/Message/RefundsRequest.php
new file mode 100644
index 0000000..a9921ce
--- /dev/null
+++ b/src/Message/RefundsRequest.php
@@ -0,0 +1,115 @@
+<?php
+
+namespace Omnipay\Przelewy24\Message;
+
+use Omnipay\Common\Exception\InvalidRequestException;
+use Omnipay\Common\Message\ResponseInterface;
+
+class RefundsRequest extends AbstractRequest
+{
+    public function setRequestId(string $requestId): self
+    {
+        return $this->setParameter('requestId', $requestId);
+    }
+
+    public function getRequestId(): string
+    {
+        return $this->getParameter('requestId');
+    }
+
+    public function setRefunds(array $refunds): self
+    {
+        return $this->setParameter('refunds', $refunds);
+    }
+
+    public function getRefunds(): array
+    {
+        return $this->getParameter('refunds');
+    }
+
+    public function setRefundsUuid(string $refundsUuid): self
+    {
+        return $this->setParameter('refundsUuid', $refundsUuid);
+    }
+
+    public function getRefundsUuid(): string
+    {
+        return $this->getParameter('refundsUuid');
+    }
+
+    public function setUrlStatus(?string $urlStatus): self
+    {
+        return $this->setParameter('urlStatus', $urlStatus);
+    }
+
+    public function getUrlStatus(): ?string
+    {
+        return $this->getParameter('urlStatus');
+    }
+
+    public function getData(): array
+    {
+        $this->validate('requestId', 'refunds', 'refundsUuid');
+        $this->validateRefundsArray();
+        $this->transformRefundsAmount();
+
+        $data = [
+            'requestId' => $this->getRequestId(),
+            'refunds' => $this->getRefunds(),
+            'refundsUuid' => $this->getRefundsUuid(),
+            'urlStatus' => $this->getUrlStatus(),
+        ];
+
+        return array_filter($data);
+    }
+
+    /**
+     * @param array $data
+     * @return ResponseInterface|MethodsResponse
+     */
+    public function sendData($data): ResponseInterface
+    {
+        $httpResponse = $this->sendRequest('GET', 'transaction/refund', $data);
+
+        $responseData = json_decode($httpResponse->getBody()->getContents(), true);
+
+        return $this->response = new RefundsResponse($this, $responseData, $this->getEndpoint());
+    }
+
+    /**
+     * @throws InvalidRequestException
+     */
+    private function validateRefundsArray(): void
+    {
+        $refunds = $this->getParameter('refunds');
+        if (is_null($refunds) || empty($refunds)) {
+            throw new InvalidRequestException("The parameter `refunds` can not be empty");
+        }
+
+        $requiredFields = ['orderId', 'sessionId', 'amount'];
+
+        foreach ($refunds as $key => $refund) {
+            if (! is_array($refund)) {
+                throw new InvalidRequestException("Values in `refunds` need to be an array");
+            }
+            foreach ($requiredFields as $requiredField) {
+                if (! array_key_exists($requiredField, $refund)) {
+                    throw new InvalidRequestException("The $requiredField parameter is required in index $key of `refunds` array");
+                }
+            }
+        }
+    }
+
+    /**
+     * @throws InvalidRequestException
+     */
+    private function transformRefundsAmount(): void
+    {
+        $refunds = $this->getParameter('refunds');
+        foreach ($refunds as $key => $refund) {
+            $refunds[$key]['amount'] = $this->internalAmountValue($refund['amount']);
+        }
+
+        $this->setParameter('refunds', $refunds);
+    }
+}
diff --git a/src/Message/RefundsResponse.php b/src/Message/RefundsResponse.php
new file mode 100644
index 0000000..90da4b2
--- /dev/null
+++ b/src/Message/RefundsResponse.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Omnipay\Przelewy24\Message;
+
+use Omnipay\Common\Message\RequestInterface;
+
+class RefundsResponse extends AbstractResponse
+{
+    private $refunds;
+
+    private $responseCode;
+
+    public function __construct(RequestInterface $request, $data, $endpoint)
+    {
+        parent::__construct($request, $data, $endpoint);
+        $this->refunds = $data['data'] ?? null;
+        if (isset($data['responseCode'])) {
+            $this->responseCode = (int) $data['responseCode'];
+        }
+    }
+
+    public function getRefunds(): array
+    {
+        return $this->refunds;
+    }
+
+    public function getResponseCode(): ?int
+    {
+        return $this->responseCode;
+    }
+
+    public function getCode(): int
+    {
+        if (! is_null($this->getResponseCode())) {
+            return $this->getResponseCode();
+        }
+
+        return parent::getCode();
+    }
+}
diff --git a/tests-api/GatewayTest.php b/tests-api/GatewayTest.php
index a54030b..092a88c 100644
--- a/tests-api/GatewayTest.php
+++ b/tests-api/GatewayTest.php
@@ -5,7 +5,6 @@
 namespace API;
 
 use Omnipay\Omnipay;
-use Omnipay\Przelewy24\Message\AbstractResponse;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\VarDumper\VarDumper;
@@ -32,7 +31,7 @@ public function setUp()
     public function testAccess(): void
     {
         $response = $this->gateway->testAccess()->send();
-        $this->assertSame(AbstractResponse::HTTP_OK, $response->getCode());
+        $this->assertSame(Response::HTTP_OK, $response->getCode());
         $this->assertSame('', $response->getMessage());
         $this->assertTrue($response->isSuccessful());
 
@@ -40,14 +39,14 @@ public function testAccess(): void
         $response = $this->gateway->testAccess()->send();
 
         $this->assertFalse($response->isSuccessful());
-        $this->assertSame(AbstractResponse::HTTP_UNAUTHORIZED, $response->getCode());
+        $this->assertSame(Response::HTTP_UNAUTHORIZED, $response->getCode());
         $this->assertSame("Incorrect authentication", $response->getMessage());
     }
 
     public function testMethods(): void
     {
         $response = $this->gateway->methods()->send();
-        $this->assertSame(AbstractResponse::HTTP_OK, $response->getCode());
+        $this->assertSame(Response::HTTP_OK, $response->getCode());
         $this->assertSame('', $response->getMessage());
         $this->assertTrue($response->isSuccessful());
         $this->assertGreaterThan(0, count($response->getMethods()));
@@ -72,7 +71,7 @@ public function testPurchase(): void
         VarDumper::dump($response->getRedirectUrl());
         VarDumper::dump($response->getMessage());
 
-        $this->assertSame(AbstractResponse::HTTP_OK, $response->getCode());
+        $this->assertSame(Response::HTTP_OK, $response->getCode());
         $this->assertSame('', $response->getMessage());
         $this->assertTrue($response->isSuccessful());
         $this->assertContains('https://sandbox.przelewy24.pl/trnRequest/', $response->getRedirectUrl());
diff --git a/tests/GatewayTest.php b/tests/GatewayTest.php
index 3b45980..3efe35e 100644
--- a/tests/GatewayTest.php
+++ b/tests/GatewayTest.php
@@ -8,6 +8,7 @@
 use Omnipay\Przelewy24\Message\MethodsRequest;
 use Omnipay\Przelewy24\Message\PurchaseInfoRequest;
 use Omnipay\Przelewy24\Message\PurchaseRequest;
+use Omnipay\Przelewy24\Message\RefundsRequest;
 use Omnipay\Przelewy24\Message\TestAccessRequest;
 use Omnipay\Tests\GatewayTestCase;
 
@@ -142,6 +143,9 @@ public function it_should_create_a_purchase()
         $this->assertSame('10.00', $request->getAmount());
     }
 
+    /**
+     * @test
+     */
     public function it_should_set_and_get_amount_on_purchase()
     {
         $request = $this->gateway->purchase([
@@ -151,6 +155,9 @@ public function it_should_set_and_get_amount_on_purchase()
         $this->assertSame('10.00', $request->getAmount());
     }
 
+    /**
+     * @test
+     */
     public function it_should_set_and_get_shipping_on_purchase()
     {
         $request = $this->gateway->purchase([
@@ -172,6 +179,33 @@ public function it_should_create_a_complete_purchase()
         $this->assertSame('10.00', $request->getAmount());
     }
 
+    /**
+     * @test
+     * @dataProvider refund_data_provider
+     */
+    public function it_should_create_a_refund(
+        string $requestId,
+        array $refunds,
+        string $refundsUuid,
+        ?string $urlStatus
+    ) {
+        $data = [
+            'requestId' => $requestId,
+            'refunds' => $refunds,
+            'refundsUuid' => $refundsUuid,
+            'urlStatus' => $urlStatus,
+        ];
+
+        $request = $this->gateway->refund($data);
+
+        $this->assertInstanceOf(RefundsRequest::class, $request);
+
+        $this->assertSame($requestId, $request->getRequestId());
+        $this->assertSame($refunds, $request->getRefunds());
+        $this->assertSame($refundsUuid, $request->getRefundsUuid());
+        $this->assertSame($urlStatus, $request->getUrlStatus());
+    }
+
     /**
      * @test
      */
@@ -182,9 +216,41 @@ public function it_should_create_a_purchase_info()
         $this->assertSame('session-id', $request->getSessionId());
     }
 
+    /**
+     * @test
+     */
     public function it_should_create_card_info()
     {
         $request = $this->gateway->cardInfo('transaction-id');
         $this->assertInstanceOf(CardInfoRequest::class, $request);
     }
+
+    public function refund_data_provider(): array
+    {
+        return [
+            [
+                'requestId' => '123',
+                'refunds' => [
+                    [
+                        'orderId' => '123',
+                        'sessionId' => '123',
+                        'amount' => '123',
+                    ],
+                ],
+                'refundsUuid' => '321',
+                'urlStatus' => 'status',
+            ],
+            [
+                'requestId' => 'gsa',
+                'refunds' => [
+                    [
+                        'orderId' => 'dfsa',
+                        'amount' => 'dsa',
+                    ],
+                ],
+                'refundsUuid' => '512',
+                'urlStatus' => '15215215',
+            ],
+        ];
+    }
 }
diff --git a/tests/Message/CompletePurchaseRequestTest.php b/tests/Message/CompletePurchaseRequestTest.php
index 94c4cb9..4648d0e 100644
--- a/tests/Message/CompletePurchaseRequestTest.php
+++ b/tests/Message/CompletePurchaseRequestTest.php
@@ -4,10 +4,10 @@
 
 namespace Message;
 
-use Omnipay\Przelewy24\Message\AbstractResponse;
 use Omnipay\Przelewy24\Message\CompletePurchaseRequest;
 use Omnipay\Przelewy24\Message\CompletePurchaseResponse;
 use Omnipay\Tests\TestCase;
+use Symfony\Component\HttpFoundation\Response;
 
 class CompletePurchaseRequestTest extends TestCase
 {
@@ -51,7 +51,7 @@ public function testSendSuccess()
         $this->assertTrue($response->isSuccessful());
         $this->assertFalse($response->isRedirect());
         $this->assertSame('', $response->getMessage());
-        $this->assertSame(AbstractResponse::HTTP_OK, $response->getCode());
+        $this->assertSame(Response::HTTP_OK, $response->getCode());
     }
 
     public function testSendFailure()
@@ -61,7 +61,7 @@ public function testSendFailure()
 
         $this->assertInstanceOf(CompletePurchaseResponse::class, $response);
         $this->assertFalse($response->isSuccessful());
-        $this->assertSame(AbstractResponse::HTTP_BAD_REQUEST, $response->getCode());
+        $this->assertSame(Response::HTTP_BAD_REQUEST, $response->getCode());
         $this->assertSame('Incorrect CRC value', $response->getMessage());
     }
 }
diff --git a/tests/Message/PurchaseRequestTest.php b/tests/Message/PurchaseRequestTest.php
index 3a03952..fd9492e 100644
--- a/tests/Message/PurchaseRequestTest.php
+++ b/tests/Message/PurchaseRequestTest.php
@@ -6,10 +6,10 @@
 
 use Omnipay\Common\CreditCard;
 use Omnipay\Przelewy24\Gateway;
-use Omnipay\Przelewy24\Message\AbstractResponse;
 use Omnipay\Przelewy24\Message\PurchaseRequest;
 use Omnipay\Przelewy24\Message\PurchaseResponse;
 use Omnipay\Tests\TestCase;
+use Symfony\Component\HttpFoundation\Response;
 
 class PurchaseRequestTest extends TestCase
 {
@@ -111,7 +111,7 @@ public function testSendSuccess()
         );
         $this->assertNull($response->getRedirectData());
         $this->assertNull($response->getTransactionReference());
-        $this->assertSame(AbstractResponse::HTTP_OK, $response->getCode());
+        $this->assertSame(Response::HTTP_OK, $response->getCode());
         $this->assertSame('', $response->getMessage());
     }
 
@@ -123,7 +123,7 @@ public function testSendSignatureFailure()
         $this->assertInstanceOf(PurchaseResponse::class, $response);
         $this->assertFalse($response->isSuccessful());
         $this->assertFalse($response->isRedirect());
-        $this->assertSame(AbstractResponse::HTTP_BAD_REQUEST, $response->getCode());
+        $this->assertSame(Response::HTTP_BAD_REQUEST, $response->getCode());
         $this->assertSame('Incorrect CRC value', $response->getMessage());
     }
 }
diff --git a/tests/Message/RefundsRequestTest.php b/tests/Message/RefundsRequestTest.php
new file mode 100644
index 0000000..4fac2ce
--- /dev/null
+++ b/tests/Message/RefundsRequestTest.php
@@ -0,0 +1,211 @@
+<?php
+
+namespace Message;
+
+use Omnipay\Common\Exception\InvalidRequestException;
+use Omnipay\Przelewy24\Message\RefundsRequest;
+use Omnipay\Przelewy24\Message\RefundsResponse;
+use Omnipay\Tests\TestCase;
+
+/**
+ * @group unit
+ */
+class RefundsRequestTest extends TestCase
+{
+    private const REQUEST_DATA = [
+        'requestId' => '123',
+        'refunds' => [
+            [
+                'orderId' => '123',
+                'sessionId' => '123',
+                'amount' => '123',
+            ],
+        ],
+        'refundsUuid' => '321',
+    ];
+
+    /**
+     * @var RefundsRequest
+     */
+    private $request;
+
+    public function setUp(): void
+    {
+        $this->request = new RefundsRequest($this->getHttpClient(), $this->getHttpRequest());
+    }
+
+    /**
+     * @dataProvider refundDataProvider
+     */
+    public function testGetData(
+        ?string $requestId,
+        array $refunds,
+        ?string $refundsUuid,
+        ?string $urlStatus,
+        ?string $expectedExceptionMessage
+    ): void {
+        $data = [];
+
+        if (! is_null($requestId)) {
+            $data['requestId'] = $requestId;
+        }
+
+        $data['refunds'] = $refunds;
+
+        if (! is_null($refundsUuid)) {
+            $data['refundsUuid'] = $refundsUuid;
+        }
+
+        if (! is_null($urlStatus)) {
+            $data['urlStatus'] = $urlStatus;
+        }
+
+        $this->request->initialize($data);
+
+        if (! is_null($expectedExceptionMessage)) {
+            $this->expectException(InvalidRequestException::class);
+            $this->expectExceptionMessage($expectedExceptionMessage);
+        }
+
+        $data = $this->request->getData();
+        $this->assertSame($requestId, $data['requestId']);
+        foreach ($refunds as $key => $refund) {
+            $this->assertSame($refund['orderId'], $data['refunds'][$key]['orderId']);
+            $this->assertSame($refund['sessionId'], $data['refunds'][$key]['sessionId']);
+            $this->assertNotSame($refund['amount'], $data['refunds'][$key]['amount']);
+        }
+        $this->assertSame($refundsUuid, $data['refundsUuid']);
+        $this->assertSame($urlStatus, $data['urlStatus']);
+    }
+
+    public function testSendSuccess(): void
+    {
+        $this->setMockHttpResponse('RefundsRequestSuccess.txt');
+        $this->request->initialize(self::REQUEST_DATA);
+        $response = $this->request->send();
+
+        $this->assertInstanceOf(RefundsResponse::class, $response);
+        $this->assertTrue($response->isSuccessful());
+        $this->assertNotNull($response->getRefunds());
+        $this->assertNotNull($response->getResponseCode());
+        $this->assertSame(1, count($response->getRefunds()));
+    }
+
+    /**
+     * @dataProvider failureResponseDataProvider
+     */
+    public function testSendFailure(string $fileName): void
+    {
+        $this->setMockHttpResponse($fileName);
+        $this->request->initialize(self::REQUEST_DATA);
+        $response = $this->request->send();
+
+        $this->assertInstanceOf(RefundsResponse::class, $response);
+        $this->assertFalse($response->isSuccessful());
+        $this->assertNotNull($response->getCode());
+        $this->assertNotNull($response->getMessage());
+        $this->assertNull($response->getResponseCode());
+    }
+
+    public function failureResponseDataProvider(): array
+    {
+        return [
+            ['RefundsRequestFailure.txt'],
+            ['RefundsRequestFailedConflict.txt'],
+            ['RefundsRequestFailedAuthorization.txt'],
+        ];
+    }
+
+    public function refundDataProvider(): array
+    {
+        return [
+            [
+                'requestId' => '123',
+                'refunds' => [
+                    [
+                        'orderId' => '123',
+                        'sessionId' => '123',
+                        'amount' => '123',
+                    ],
+                ],
+                'refundsUuid' => '321',
+                'urlStatus' => 'status',
+                'expectedExceptionMessage' => null,
+            ],
+            [
+                'requestId' => 'gsa',
+                'refunds' => [
+                    [
+                        'orderId' => 'dfsa',
+                        'amount' => 'dsa',
+                    ],
+                ],
+                'refundsUuid' => '512',
+                'urlStatus' => '15215215',
+                'expectedExceptionMessage' => 'The sessionId parameter is required in index 0 of `refunds` array',
+            ],
+            [
+                'requestId' => 'gsa',
+                'refunds' => [
+                    [
+                        'amount' => 'dsa',
+                    ],
+                ],
+                'refundsUuid' => '512',
+                'urlStatus' => '15215215',
+                'expectedExceptionMessage' => 'The orderId parameter is required in index 0 of `refunds` array',
+            ],
+            [
+                'requestId' => 'gsa',
+                'refunds' => [],
+                'refundsUuid' => '512',
+                'urlStatus' => '15215215',
+                'expectedExceptionMessage' => 'The parameter `refunds` can not be empty',
+            ],
+            [
+                'requestId' => 'gsa',
+                'refunds' => [1, 23],
+                'refundsUuid' => '512',
+                'urlStatus' => '15215215',
+                'expectedExceptionMessage' => 'Values in `refunds` need to be an array',
+            ],
+            [
+                'requestId' => null,
+                'refunds' => [1, 23],
+                'refundsUuid' => null,
+                'urlStatus' => '',
+                'expectedExceptionMessage' => 'The requestId parameter is required',
+            ],
+            [
+                'requestId' => '123',
+                'refunds' => [
+                    [
+                        'orderId' => '123',
+                        'sessionId' => '123',
+                        'amount' => '123',
+                    ],
+                ],
+                'refundsUuid' => null,
+                'urlStatus' => '',
+                'expectedExceptionMessage' => 'The refundsUuid parameter is required',
+            ],
+            [
+                'requestId' => '123',
+                'refunds' => [
+                    [
+                        'orderId' => '123',
+                        'sessionId' => '123',
+                        'amount' => '123',
+                    ],
+                    [
+                        'sessionId' => '123',
+                        'amount' => '123',
+                    ],
+                ],
+                'refundsUuid' => '123',
+                'urlStatus' => null,
+                'expectedExceptionMessage' => 'The orderId parameter is required in index 1 of `refunds` array',
+            ],
+        ];
+    }
+}
diff --git a/tests/Mock/RefundsRequestFailedAuthorization.txt b/tests/Mock/RefundsRequestFailedAuthorization.txt
new file mode 100644
index 0000000..8fdd928
--- /dev/null
+++ b/tests/Mock/RefundsRequestFailedAuthorization.txt
@@ -0,0 +1,9 @@
+HTTP/1.1 401 Created
+Server: nginx/1.4.4
+Date: Sat, 14 May 2022 14:00:00 GMT
+Content-Type: application/json; charset=utf-8
+Connection: keep-alive
+Cache-Control: no-cache, no-store
+X-Request-Id: 53e398c2-1c9a-4e8b-a3a7-9dcf3cad90b1
+
+{"code": "401", "error": "Incorrect authentication"}
diff --git a/tests/Mock/RefundsRequestFailedConflict.txt b/tests/Mock/RefundsRequestFailedConflict.txt
new file mode 100644
index 0000000..0f97e70
--- /dev/null
+++ b/tests/Mock/RefundsRequestFailedConflict.txt
@@ -0,0 +1,9 @@
+HTTP/1.1 401 Created
+Server: nginx/1.4.4
+Date: Sat, 14 May 2022 14:00:00 GMT
+Content-Type: application/json; charset=utf-8
+Connection: keep-alive
+Cache-Control: no-cache, no-store
+X-Request-Id: 53e398c2-1c9a-4e8b-a3a7-9dcf3cad90b1
+
+{"code": "409", "error": []}
diff --git a/tests/Mock/RefundsRequestFailure.txt b/tests/Mock/RefundsRequestFailure.txt
new file mode 100644
index 0000000..a4e5cc6
--- /dev/null
+++ b/tests/Mock/RefundsRequestFailure.txt
@@ -0,0 +1,9 @@
+HTTP/1.1 400 Created
+Server: nginx/1.4.4
+Date: Sat, 14 May 2022 14:00:00 GMT
+Content-Type: application/json; charset=utf-8
+Connection: keep-alive
+Cache-Control: no-cache, no-store
+X-Request-Id: 53e398c2-1c9a-4e8b-a3a7-9dcf3cad90b1
+
+{"code": "400", "error": "Invalid input parameters"}
diff --git a/tests/Mock/RefundsRequestSuccess.txt b/tests/Mock/RefundsRequestSuccess.txt
new file mode 100644
index 0000000..ce85ce6
--- /dev/null
+++ b/tests/Mock/RefundsRequestSuccess.txt
@@ -0,0 +1,9 @@
+HTTP/1.1 201 Created
+Server: nginx/1.4.4
+Date: Sat, 14 May 2022 14:00:00 GMT
+Content-Type: application/json; charset=utf-8
+Connection: keep-alive
+Cache-Control: no-cache, no-store
+X-Request-Id: 53e398c2-1c9a-4e8b-a3a7-9dcf3cad90b1
+
+{"responseCode": "201", "data": [ {"orderId": 1, "sessionId": 2, "amount": 2, "description": "test", "status": 1, "message": "test-message" } ]}