diff --git a/app/services/check_user_service.py b/app/services/check_user_service.py
index 99d205a..bbd4c51 100644
--- a/app/services/check_user_service.py
+++ b/app/services/check_user_service.py
@@ -1,6 +1,6 @@
 import logging
 import authorizenet.apicontrollers as controllers
-from authorizenet import apicontractsv1
+from authorizenet import apicontractsv1, constants
 
 logger = logging.getLogger(__name__)
 from .. import crud, database, schemas