Poor Quality and Poorer Service

I am really getting irritated with the service I am receiving from Cell C. A few months ago I had to do a sim swap because the Sim I had just suddenly failed to connect to the Network. Bare in mind that it costs R140 to do a sim swap at your retail stores, while the other networks charge between R50 and R90. Then a week ago I the "new" sim I bought only a few months ago did the same thing, just stopped picking up the network. I went to the store where I bought it in Campus Square and your sales assistant told me that it wasn't their problem and that I will have to purchase another for R140. Clearly your sim cards are faulty cause I have a Vodacom sim and I haven't had any issues with it since I received it 3 years ago and I have used it in the same devices I use your sim in. I refuse to pay for another sim again and if this issue is not resolved I will contact ICASA and have them test this sim.