Unable to cancel contracts

I have been trying since June 2022 to cancel my existing 2 contracts with MTN. I no longer need them and I don't use them. Not interested to renew. I have phoned so many times to cancel these contracts. They said at first it has to be on pre-paid. Accepted. But this means no debit order deduction, yet they have been taking it every month since. Last month when I spoke to them they indicated that only one account was cancelled (keeping in mind that the full amount for both contracts were still being deducted monthly) but the other has a ticket open which was opened at the branch for the cancellation. They managed to cancel this ticket but yet again my account has been deducted. It is extremely difficult to get through to the correct department. I was put through from one person to the next and then another. Eventually being so aggravated with the fact that no one can assist. The branches cannot assist in any way. I am fed up.