Charging clients for their default sim cards they send with contracts!!!!

This is upsetting that we have to resolve to complaining about a service provider which we have supported for such a long time, first we get staff helping you at the clearwater mall branch that think that they do you a favor by helping you!!! worst attitude and customer service. Now if that is not enough, you take a new contract, have the sim in your phone for a month and after a software update, the sim dont work anymore. So how is it that a sim Cell C provided with a contract, is faulty after a month and I have to pay for a sim swap, If we have to pay for a sim swap every month becuase CELL C's sims is ****, then it will cost us a fortune on the end of the day!!! I need an explanation to this, because I will contact the ombutsman about this!!