Poor Communication by Pep Randridge mall employees

I went to Pep store in Randridge mall,I asked for a Voucher,they did not explain they have different types of Vouchers,they have me a Voucher for Hollywood bets apparently,now they can't help me,they keep on telling me the lady who helped me is not at work.the Supervisor who was working today 04/01 said I should have known there are different Vouchers,I seldomly use Pep,How would I know?I want my money back