ITC update

My cellphone contract with cell c was handed over for collections with some debt collecting company. I paid the settlement amount but the debt collector said it is cell c tha has to remove my name from itc. I tried contacting cell c with no success. Sent them my paid up letter. 6 months and still no update. I stopped paying them cause their sim card lasts for 2 months. What kind of sim card gets damaged whilst inside a phone. Used MTN for years but no sim card of mine ever crashed. They make money from is by selling useless sim cards and you are liable for sim swaps.