Poor service from wesbank

I obtained a setlement figure ref *** : Settlement letter of Debt - I settled in full on the 25th September and notified wesbank accordingly on the same day. I requested that the debit order not be raised for the next debit but it was. I have been trying since then to get a refund of the full amount but without success. Lots of promises but still no refund. The debit order cannot be cancelled on my FNB account as they do not allow you to cancell with one of their own.