Bad service

bad service my contract was ending in august 2020 i did email them the end of august and told then im not going to upgrade my contract im going to end the contract , i did get a reference number Reference***, in november i called them for a proof of cancellation they told me they never received my email and they had a technical problem which is not my problem because i did get a reference number , when i gave them the reference number they told me they never only see the email now but i must send them the outstanding fees, i asked them to send me a statement that shows im missed a payment up until today i never got a respond from them, 2 months ago i received a email that my account has been handed over i must make arrangement and i explained to them the process and MTN must call me because they never send me statements or even responded on my emails up until today... im tired of all the calls i received 5 times a day about a contract that ended