Debit Order Nightmare

Very unhappy with Cell C, I used to be a customer of Cell C for many years but will never ever use them again. Last year November 2019 I gave them A months notice on a month to month data contract I had with them because that's what I was told to do when I contacted them to find out how I should go about doing it. The month notice went past and December 2019 they took another debit order which I reversed. January 2020 they took another debit order which I reversed again and this happened in February 2020 again. I contacted them and was told by a call Centre agent as they call themselves that on their side it shows the contract no longer exists so when I asked them to explain why then do they still run a debit order I was told to hold on they have to transfer me to their finance dept. I held on for more than 10 min with nobody answering my call before I dropped the call. The debit orders stopped from March 2020 and I thought it was sorted out. 6 months later in October 2020 they decided out of the blue to start running a debit order again I mean ***!!!! I need someone from Cell C to contact me and explain what in the world is going on here!! ***