Un known Vodacom contract

Hello Peter the past two years I had a contract with vodacom, it had to end in August 2019 were I asked them to cancel it unfortunately when I called in vodacom contracts services they referred me to vodacom cancelation service, when I called in I was told that vodacom contracts are still busy with my contract, and it was the same story each time I call, I then now started to receive a msg saying I'm owing vodacom R933,when I call in to ask about what is going on , why am I still owing vodacom because I asked for cancelation, then I was told that the process is going on of me canceling my contract I should the ask for proposed invoice, I did so but unfortunately I was told that I'm owing vodacom, I then called again to ask what do I do, immediately when I call to introduce my name to them, they put my call on voice aunthitication,and I called in the following day and they upgraded my contract without my knowledge and they keep moving in circles, please I can't pay for a contract which I requested to be canceled ***