they don't want to do my sim swop

I'm so fed up with cell c.....on the 18th pf February 2015 my cell c sim card just stopped working, on the phone it was written no network found. Few hours later I realised it was still the same, I took the sim card n put it on another phone but same thing happened. I phoned customer care and they asked me the color of the sim and I told them its blue, they told me those blue sim has that problem of loosing network I must go and buy the black sim card and so I did bought it. On Saturday I wanted to do the sim swop they told me the department for sim swop is working on Monday to Friday and I understood, on Monday morning I phoned customer care again they took my details n told me that an agent from sim swop department will phone me back on Tuesday.... I waited for the call the whole day on Tuesday n no body phoned me. They also told me they are going to charge me R50 to do a sim swop even if the problem is on their side. For almost a week I can't use my phone for something that is not my problem. I'm beginning to think they are also fed up with me as the customer #disgusted n ****ed off with cell c