Sim card not working

I've been a Cell C customer for more than 10 years. The last upgrade I took had problems after few months of my upgrade. After 3 months had problem with the sim card and was told to do a sim swap because the chip was damaged. I did it and after a month had the same problem again. I can't work for sim swap it's too expensive. No one is willing to help me with this I've called Cell C sent emails and sent to Hellopeter more than once but still no joy. Poor service!!!!!!