FED UP

I don't know how they do their jobs because all I get is terrible service. firstly I wanted to upgrade one of my 3 contracts I have with MTN (at the time there was 2 that could upgrade) I wanted to upgrade one and cancel the other one, so they upgraded the wrong one and couldn't fix the problem so I had to upgrade the other one as well ( the one I wanted to cancel) then I decided to cancel the 3rd contract but it wasn't due so I paid a heavy amount for early cancelation, to cancel and phoned in and everything just to hear that it wasn't canceled and that they used that money for my monthly subscription, and then i said to them they should fix the problem and nobody can help me I'm fed up with the service I'm getting I'm paying a lot of money for my contracts but nobody can assist me.