how hard is it to get a sim swop

I recently ugraded my cell c contract and I got a new phone 3 weeks ago....since then my sim card is not working.I have asked to do a sim swop on my old number but I can not get any help over the phone...I keep getting transfered from one agent to another.The other irritating thing is that for the past year I have been paying for a non existing phone and sim because I lost my phone and sim last year but because I did not take out insurance cell c could not give me a new phone or sim...so I waited until this year to renew the contract.My excitement has turned into disappointment because cell c agents cannot do a sim swop on my sim card...therefore it means I cannot have cell c benefits on my new contract phone.The ref number I was given is ***...I am going to try them after an hour