diff --git a/src/Message/p2p/CompletePurchaseResponse.php b/src/Message/p2p/CompletePurchaseResponse.php
index 3259b62..68a6c67 100644
--- a/src/Message/p2p/CompletePurchaseResponse.php
+++ b/src/Message/p2p/CompletePurchaseResponse.php
@@ -238,7 +238,7 @@ public function calculateHash()
 
     public function getFee()
     {
-        return (string)($this->getAmount() - $this->getWithdrawAmount());
+        return (string)($this->getWithdrawAmount()-$this->getAmount());
     }
 
     public function getAmount()