Mtn is not responding to my complaints, I am paying for a contract I ended 3 months ago

Frustrated;

I have cancelled one of my Mtn contracts, in October(Early October), was advised there's an early cancellation fee , which I paid but im still being billed for that contract 3 months later. I have send numerous emails trying to get assistance but they do not reply, they simply do not care. I have also been calling their call centre , the consultants never know anything and its different stories everytime I call in. I have been calling from the time I have cancelled the contract until today (Dec 20th ) , the retentions department consultants are also just telling me different stories, as if it wasn't bad enough that we are put on Hold for more than 30 minutes at a time, now they simply disconnect the call and you'll be left with no choice but to call them again and waste another hour with the hopes that they will pick up the call. I am at the end of the rope, I do not know what else to do with Mtn, I have also asked for a breakdown of my bill and as usual the consultants say that the system is not responding and again one has to call in again. Mtn does not care about their customers and I doubt they have any customer service processess /skills training because that's evident with the type of service we receive, no sense of urgency and you will literally be talking to yourself when you need help. The only time Mtn cares about customers is when they are signing you in, one you are in they dont give a damn what happens.