Same happened to me. But,it was EAD and AP applications that were pending.
Based on the Cust rep,i placed a hold on the cheque,since they were not cashed yet.
But,got a collection agency notice to pay,since it is the Filing Fee and not application/processing fee.
So,all you can do is just feel happy for the GC and forget about the Filing fee.
I know,it sucks !!