6 AT&T Customer Service Reps and still no resolution

I have been on the phone with 6 different customer service reps and none of them have been able to resolve my issue.   Issue— I cancelled my at&t prepaid gophone data plan for my iPad but I was still charged.  I contacted at&t when the charges appeared and they stated they will issue a refund check.  It has now been over 45 days and still no check.  I called at&t tonight and after speaking with 6 customer service reps I have no resolution.  I cancelled the account on January 11 and between then and now, Att gave the number to another customer.  Now they claim they can’t find any info for my account and no record of a refund.  Helppp 

So unhappy with Att