account billing

In May 2015 my account was over billed by R460. I tried calling their customer care but it was during the strike so could not find them. I then sent an email requesting that they look into this. No feedback was given. Come June 2015, they sent a bill with this amount from May. Again I wrote to query the bill. I continued paying my normal subscriptions whilst quiring this other amount. June past but no response for May and nothing for June. Come July 2015, the bill came with this extra amount from May. Again I wrote to quiry this amount and paid my normal subscriptions. When August started they suspended my out going services because of this outstanding amount without giving me the feedback on my quiries. I had to pay this amount so I can be able to use my phones but I hate mtn with my whole life. Just waiting for these contracts to expire then am gone. And will take my girlfriend and my son to vodacom with this number porting thing. I have a very tight budget but had to get this R460 so that can be able to use my phones