diff --git a/src/PaymentMethods/InstructionStrategies/CreditcardInstructionStrategy.php b/src/PaymentMethods/InstructionStrategies/CreditcardInstructionStrategy.php
index 2d66824e..4723094c 100644
--- a/src/PaymentMethods/InstructionStrategies/CreditcardInstructionStrategy.php
+++ b/src/PaymentMethods/InstructionStrategies/CreditcardInstructionStrategy.php
@@ -14,10 +14,11 @@ public function execute(
     ) {
 
         if ($payment->isPaid() && $payment->details) {
+            $cardHolder = isset($payment->details->cardHolder) ? $payment->details->cardHolder : 'Unknown';
             return sprintf(
             /* translators: Placeholder 1: card holder */
                 __('Payment completed by <strong>%s</strong>', 'mollie-payments-for-woocommerce'),
-                $payment->details->cardHolder
+                $cardHolder
             );
         }
         $defaultStrategy = new DefaultInstructionStrategy();