Old Sim Card not reading

Hello Peter I come back again with the same issue my Cellc Sim Card is not reading on my phone I went to the store and was advised to buy none ricad sim card and called customer care the guy who assisted me the first time hang up didn't get his name second guy Martin Bagoloe was very impatient and didn't help I'm tired of this run around please assist the reason I'm still even a Cell C customer is that my number is linked to my Financials e.g banks and other online activities I would like to be assisted by activating my Sim have answered security questions I could remember and am told the system has failed my responses I have this number for more than 12 years I don't want to loose it please