MTN account charging for non-existent contract.

After going through all required procedures in transferring a contract MTN Cell service to the prepaid version on the same cell number AND having this confirmed as a successful transfer after the required notice period and process was completed. I am still being charged on the old debit order for the contract (Now non-existent). Have tried on 7 calls to have this attended to by MTN with no success whatsoever. I am now being charged for the non-existent contract as well as having to purchase "pay as you go" bundles. There appears to be no magic formula to have this incompetence corrected.