Empty Promises and Billing mistakes

I have been re-rated only two months after my previous re-rate. According to the two call center agents and the Credit controller I spoke to this is incorrect.<br> <br> I have received verbal confirmation of the mistake as well as received commitment from ADT's representative to reimburse me for the incorrect amount billed(now for a second month in a row) and to correct the mistake.<br> <br> This has not occurred and I have not received any communication after I have phoned for a third time requesting someone contact me.<br> <br> Please assist.