Paid settlement but still being charged

I took up a contract for 2 phones with Telkom In December 2021. 2022 April/May I requested a settlement amount and requested that they stop all services. I was given the settlement amount and paid. I thought everything was over until December 2022. Telkom started deducting from my account all of a sudden. I was surprised as to what is happening. I called them to ask what was happening. They told me I paid but did not close the account. This was the most ridiculous thing I have ever had. I was clear even in my cancellation that I am ending my relationship and terminating everything I had with them. Telkom just continued accessing my account and doing as they please. I paid up everything but was treated like a none paying customer. They took my money and kept wanting more claiming I was still subscribed to their data services and all. Immediately after settling I did away with their SIM cards as they were no longer of use. I had stopped everything. While I explicitly told them that I was cancelling everything. They chose what to cancel and what to leave despite what a client wants. Now I am being harassed by the so called debt collectors. Calling me and making me a bad payer.

Please assist because I hate being harassed by Telkom and their debt collectors.