Bad service on cancellation of contract and refund

On the 1st of Nov 2017 I phoned Cell C to cancel my contract, giving a month's notice. In Dec/Jan they deducted money from my account again, so I phoned them on 2 Feb 2018. No contract was cancelled!! So they only cancelled it then, but confirmed that I made a call on 1 Nov 2017 - this will be investigated. I phoned twice after that (no feedback from Cell C to date), just to hear that nothings been done and it will be referred to the customer care department. This is pathetic service!! I want feedback and a refund from Dec to date