3G contract not working

For the past few months, my Cell C sim card has not allowed internet browsing from any location or using any device (including mobile phones tested at Pavilion and Gateway Cell C branches). Cell C staff have continuously tried to pin the problem on my devices (****le, wifi router, tablet). I did a sim swap, which costed over R100 and this did not help. Two weeks ago at Cell C Gateway, a technician (Siyanda) found that the APN setting on the sim card's account was not checked. This setting was on the Cell C network and not my devices. After this was resolved the sim card worked for a few days and then stopped working. I phoned Cell C today (15-04-2015) and spent ages on the phone logging a fault only to find out that the fault had been incorrectly logged and I was told to phone some other department and relog the call. I demand a that the contract be terminated as Cell C is not providing the service that we are being charged for. I also want a refund for the months when the service has not been available.