Poor service

I went to Pep Home Kokstad to take out the cell phone that I did lay bye and I was specific when I did lay bye that I don't want vodacom phone I want mtn but when I took out my lay bye I was given vodacom and the manager and the teller convinced me that it's taking both Sim cards mtn and vodacom. Now the mtn simcard is not working on that phone and they are refusing to help me and the manager is actually rude. She says I took the phone so I can't bring it back.