*********** staff - Googleplay voucher

I bought a Googleplay voucher at the Tygervalley branch, but the lady at the till never activated the voucher. I went back to the store to tell them of the problem, they kept telling me I need to give them the activation code which I don't have. They then enquired from head office who said the card is activated, but still it shows a zero balance. They said I must contact Google now to fix the issue. Google rep**** that the store never activated the card. So now I have to go back again. This is really causing unnecessary admin which would have been prevented if the staff were competent to know what to do in the first place. I really hope they are going to give me a refund now, otherwise they basically stole the money.