Bad service from MTN

I took out a data simcard 2 years ago. It did not serve the purpose it was intended. The data was sometimes never loaded and just not a good deal. I called to cancel it. Made a payment of R630 to close it. Few months later when I wanted to take out a contract, I found out that account is still opened and given over to lawyers. I immediately took action and they send me a closure amount of R1800. I made the payment again and requested it to be closed. I'm calling every number I can find to help me but with no success. I am so disappointed that no one can help me. I have paid huge amounts to get this thing sorted. I dont know what to do anymore. This is the worst service.