If you received temporary AOR, using the temporary application number given to you, you can call IRCC to check the status of your application. If it has been returned, they will be able to confirm this detail and the date that the application was returned. If your application was found to be complete after the initial check, they will let you know and tell you that the status of the application is deemed complete.
If they say that the initial check was not completed, well, you will just have to call back and keep checking your application.
Also, do you have a copy of the documents you sent to them? If so, you should know if you did not include the postal code.