Cell C - we make mistakes, but you pay for them

I took out an unlimited 24 month contract with the intention of canceling it when I dont need it anymore. It was for my assistant. I phoned cell c’s customer services and cancelled the contract on the 16th November 2017, yet I am still debited. Cell C confirms the call was made and that I asked them to terminate the contract yet its still going. Guess what the issue is..... I neglected to ask them to transfer the call to cancellations? I am sorry, its not my responsibility to know where to transfer calls, its the call centre agents. To add fuel to the fire, she cancelled the wrong number, a pre-paid number? I have phoned the cancellations department numerous times with litte joy. Any advice anyone? I need to resolve this as Cell C is Naedo-ing my account.