MTN - Customer Service is Pathetic

I have been trying to get MTN to cancel an upgrade which they did on my account for more than a week.

Instead they have cancelled my contract completely and my account had a negative balance with them owing me money so they've taken my money and cancelled my contract by transferring me to a prepaid account.

Now I can't get through to anyone that can assist me, they keep transferring me from department to department and then cutting me off without assisting me