Bad service

I bought an iPhone online it came with a sim that was not working went to MTN Dobsonville mall a guy called Refilwe assisted me and he rica’d the SIM card unfortunately it still did not work returned the following day he was not there came across a rude white lady who wore glasses she did not even let me speak she just told me I shouldn’t bring online problems to them I should go to istore how can I go to istore if I have a problem with my sim and I took the contract with MTN bad service you should hire stuff who actually want to work