Data contract cancellation

I am not happy with MTN. Their services is very poor. I had a data contract with them that ended in October 2021. However, they say the contract was supposed to be closed manually through a phone call. Which I find not logical because I open the account in store but I’m unable to close it there. That’s not making any sense. Ok, I ended up calling MTN on January 2022 and the consultant confirmed that the account will be closed. Now to my surprise, in February they debit money from my account, and I called them to report this. The last words they told me is that they are investigating the matter. So, this month (March) they debited the money again. Does that mean the investigation requires them to constantly take my money? I am really confused here. Their famous words “please note our calls are recorded for quality and assurance purposes .” Is this quality? MTN I want my money and please cancel the contract. Thanks.