MTN keeps debiting my account for an expired contract that was cancelled months ago!

My MTN contract ended in June. I have been requesting cancellation since 26 May and to this date I am still being billed even though I have confirmed cancellation over the telephone. They have continued to deduct my account although cancellation was confirmed and contract had expired. They also continued to deduct the same amount which included the device with the addition of the data. Getting through to their accounts department is near impossible and don't hold your breath waiting for an email reply. Seems that pay as you go is the only way to go.