Unsatiesfied service

i bought a sim card today at the pep cell shop today in midrand(boulders mall), i had the latest proof of address and my id to rica the simcard, i get home put the sim in my phone, the simcard is not working i called MTN call center and walla the simcard is not ricad. how can he do that, this is inconviniencing , i have to go back to the store to rica the card. this is what we call bad service. very poor service. you dont do this to people.