I keep getting charged for a contract I cancelled

I am at my wits end and don’t know what to do anymore! I called the cancellations department on the 10th of July to cancel my contract (that expired over a year ago), due to the fact that the call cut out, I called again on the 28th of July to confirm that it was in fact cancelled, I was told it was cancelled and that July is the last month I would be debited. When I tried to do a sim swap in the middle of August (I was switching to MTN), it was not possible as I was told I still have an active contract. I phoned cancellations again and requested cancellation with immediate effect, I was told my recorded calls from July would be sent for investigation to cancel with immediate effect and heard nothing back. In the meantime, MTN did a contract to contract sim swap.

My account was then debited at the end of August. I then phoned in the middle of September to find out what was going on and was told that it was still not cancelled. The lady told me she would cancel it and process a credit on my account for the August month as she could see I had called numerous times to cancel my contract. Once again at the end of September now, my account was yet again debited!!!!

This is absolutely ridiculous, why is it so hard to cancel a contract that had already expired?? Obviously calling the call centre many many times has not proven helpful at all and I am at my wits end on what to do now. I don't have excess funds to be paying a contract I don't even have anymore and have in fact not had for over a month and half. I will be taking this matter further if it is not resolved timeously as I am now fed up!!!!