Cell C contract

I have sent numerous mails to Cell C. They debit my bank account every month with R279 for a contract that i dont have with them. No one at their call centre can supply me with any signed documentation that i took up a contract with them. I dont even have a cell c sim card, and have never activated a sim card in any of my devices. They now want to hand me over to the credit bureau because i stopped the debit order. I have sent countless mails and received a ref number that they received the mails. Guess what... they still havent phoned me to sort out the matter... just for the money. And then their consultants that phone are rude and they shout at you! She even slammed the phone in my ear. Until the matter is sorted, i am going to keep on reversing the debit order. We will see who pays who at the end of the day.