Why do I need to pay for a sim swop

I have seriously had my fair share with Cell C, but this is the limit. I did an upgrade and the wrong sim was sent for the fone, now Cell C wants me to pay for a sim swop, I mean really this was an upgrade. How do I pay for something that you guys had to make sure was in the packaging. I am seriously considering cancelling my contract cause now I get told one to either pay or wait 7 days for a new sim.