Faulty Sim card

Did not have service on my phone for more than a week. Called Cell C & was told to visit one of their stores. Went to Cell C at Galleria mall (Amanzimtoti) whilst on vacation and was asked to pay R100 for sim swap, where they removed the old sim and inserted the new one and was asked to keep my phone off for 12 hrs. Tried re-booting the phone after 18hrs and still no service. I was back home from vacation & therefore could not drive back 150km to Galleria store. So I went to one of our local Cell C store in Stanger where they removed the sim and re-inserted it but stated that device should have been off when this was done. My device was back in service immediately. A week later I'm back to square one, \no service". Contacted Cell C again & was told that all blue sim cards are faulty and should have got a black sim card. How on earth am I supposed to know that. Why are your stores selling faulty sim cards? should I now pay for another sim card? I am being charged monthly yet not enjoying the services as supposed to. Please email all feedback to [Email Removed] since my phone is out of service."""