Service disconnected unfairly due to incorrect billing.

I have experienced the worse service from Multichoice, I've called them numerous times, wasting my minutes on an issue caused by them,they billed me incorrectly, almost * 3 the amount I was supposed to pay. When I asked them to investigate this issue, I was informed that I was going to be called back. I have been waiting for weeks. Unfortunately I reversed the R1500 they billed me as I was supposed to pay R600 and I told them I would only pay if they fix my billing. They haven't sorted that and now they have deactivated my account. It's no wonder people are going for other options. Thier service is bad. Numerious agents have informed me that they have escalated the matter and I would get a callback with 48 hrs and that hasn't happened. I need my services to be activated whilst hey investigate this matter urgently and I hope I don't get billed incorrectly again on the next debit order.