diff --git a/src/Message/CompletePurchaseRequest.php b/src/Message/CompletePurchaseRequest.php
index 242de3b..e42b462 100644
--- a/src/Message/CompletePurchaseRequest.php
+++ b/src/Message/CompletePurchaseRequest.php
@@ -234,10 +234,10 @@ protected function generatePreSKey($fallbackMode = false)
     {
         $this->validate('amount', 'currency', 'domain', 'status', 'transactionId', 'transactionReference');
 
-        $preSKey = md5($this->getTransactionReference().$this->getTransactionId().$this->getStatus().$this->getDomain().$this->getAmount()->getFormatted().$this->getCurrency());
+        $preSKey = md5($this->getTransactionReference().$this->getTransactionId().$this->getStatus().$this->getDomain().$this->getAmount().$this->getCurrency());
 
         if ($fallbackMode) {
-            $preSKey = md5($this->getTransactionReference().$this->getTransactionId().$this->getStatus().$this->getDomain().$this->getAmount()->getFormatted().$this->getConvertedCurrency());
+            $preSKey = md5($this->getTransactionReference().$this->getTransactionId().$this->getStatus().$this->getDomain().$this->getAmount().$this->getConvertedCurrency());
         }
 
         return $preSKey;