Cancellation of Contracts

I've been trying for days to cancel a contract with Cell C. Calls to the cancellations line (084143) goes to the call centre. The agent ask 5 security questions and attempts to put you through. Then you go back to the call centre. Another agents asks 5 security questions and attempts to put you through. And so you go around in an endless loop. You can't cancel at a shop. Everyone says the only option is to call 084143, but you cannot get through to them.