Cell C not issuing my with paid up letter after many request

Cell C non-compliance in issuing me with a paid-up letter to remove them from my credit profile cause it still shows every month that the account is active. My contract was terminated September 2020 the payment track stopped, then suddently 2021 the payment track showed up as if the account is actived every month till now. I have called them serveral time request a paid-up letter and I always told them will sms me a reference number and someone will contact me to issues the letter. Funny thing is the next call I get from them is an agent trying to sell me a contract and they do that everytime.