diff --git a/resources/js/event_billing.js b/resources/js/event_billing.js
index 68bac3a..df15a79 100644
--- a/resources/js/event_billing.js
+++ b/resources/js/event_billing.js
@@ -105,6 +105,9 @@ EventBilling = (function () {
                 alert("Es ist ein Fehler aufgetreten!");
             }
         });
+        if(res == null){
+            return null;
+        }
         if(typeof res !== 'object'){
             return res;
         }