Sim card damaged after 4 days d

I have 4 contract with cell c n have tried to maintain my payment of R3100 avarage every month even during lockdown. No default. One of my phones takes 2 sim, i used my data sim n other sim on one phone. It stopped working, i called cell c n i was told to swap sims n also test it on another device. I eventually went to a cell x store n paid R116 for a sim swap, after 4 hours it worked. 3 days later same problem again, i m told to do sim swap. This is wrong n cell c is intentionally issuing damaged sim card to make money