Cell c Nightmare

This is probably the second time I write here because it seems like its the only time I get called by somebody from cellc because they care more about their image rather than them caring about their customers forgetting that we build that brand not them. I had a contract in 2016 with them, they failed to tell me that you needed to call them if you wanted to cancel. My contract was suppose to end in Oct 2018 but I called and told them that I wanted to settle my contract balance, I thought by settling my balance it automatically cancels the contract. They gave me the balance and I settled in June 2018 again failing to tell me that I needed to call to settle the contract. Fast forward the year 2021 cell c is still trying to debit my money after multiple attempts to call them. I sent countless emails. The last time I called they said they would investigate what happened because there was intention to cancel on my side clearly oh and they said they don't get a recording of me wanting to cancel but I received an email stating that they acknowledged my wish to cancel. I requested them to send me the contract that I signed clearly stating that I needed to call to cancel my contract but they haven't done that either. I'm really sick of this because its reflecting badly on my credit profile and that passes me off.