Cell renewed my contract without my consent

I had a contract with cell c for more than 10 years, very loyal, last year when I wanted to renew my contract they did not have the device that I wanted, I phoned them to cancel my contract, was told to phone before the 15th of the month which I did, month end money was deducted, I didn't have a problem, deducted again for another 2 months, I reversed the money and I got a call from cell c, after explaining my problem I was told that instead of canceling my contract, it was renewed without my consent, my account was then handed over to the lawyers, I have paid R1800, which is a lot,surely cell c does not know what is customer care