MTN to close the account and stop billing me for something I do not use

Last year December my contract with MTN ended so because I knew it ended I stopped using the sim card the next thing they started billing me then I took it was a mistake as I knew I no longer had a contract with them. I reversed the money and the following month they did the same and I did it again. Then started communicating with them to ask what is going on and they said the contract was automatically turned into a month to month then I said to them but I did not consent to that. They said it is like that. I asked them to cancel it and informed then that I had been receiving calls to updrage and I kept on telling them I do not want to upgrade and even the previous contract I don't want to continue with. Then they said it was never recorded. I started communicating with them via emails because sometimes you will stay online for a long time without them answering calls. Then I sent everything they asked for via email but still did not resolve my matter and did not close the account now they send me bills to pay and it goes up every month. This month I had decided I am. Going to pay that account even though I felt it is unfair to pay for something I am not using. I only wanna pay because it is affecting my credit score so to my surprise the bill went up again so it surprises me that how does it go up while I am in communication with them? Now I won't afford to pay it as it went up and I wanted to get done with it and move on with my life. Yesterday I called again and made the person aware that I have been in communication since around two months back and she said the ones who work with emails are different people so with them they do not have that information I said I have been communicating. My question is why dont they update each other then as they said their calls are recorded. They even said thru can5 close the account because of the amount outstanding so my thing I was saying they should stop the month to month thing so that the bill should not go up again this month for something that I do not want. I want mtn to close that account I do not want it I don't know how many times should I sat one thing. I am willing to make arrangements as I stated yesterday but not for that full amount because it is a lot for something I do not use. MTN is just nonsense to be honest because imagine I have been communicating with them but they do this.