Bad service

I am disgusted by the service I got from this company, and I believe I have been a loyal customer. Last month (October) I phoned the company because I had issues with my router,I had no signal. The agent advised me to do a sim swap because my sim was faulty. I went to a cell c shop in Trade Route with my router and the guy told me it was the sim that was faulty I need to do a sim swap. I did a sim swap, after a couple of days had the same issue and they said it could be my router they will will escalate the issue and call me back, and they never did. Two weeks later same issue both the sim and router not working. When I went to the shop I was told that the router damage my sim. They will need to book my router in and I have to do another sim swap. I haven't paid for the last sim swap and now I am expected to pay for another sim swap. All this time they did see that the issue was the router? I will not pay for another sim swap