MTN Contract Issue

Hi, I have cancelled my number and I have called into your call centre on numerous occasions and have on two occasions confirmed with your retentions department that I will not be debited any further. Yet this month your company has debited my account again. Very frustrating can you please reverse the debit order and have my monies paid back into my account. The number has already even been cancelled and contract has come to an end. Please advise on the way forward prior to me taking legal action as I have all call references.