iTunes card not activated

I bought an iTunes card in Checkers at Kolonnade centre for the value of R150 and the teller just tilled the card and gave it to me and when I arrived home I tried to redeem but it says that the card is not properly activated,I took the card back to the store and the customer service consultant enquired about the transaction and made the copies of receipts.i went to the store to enquire but I was sent from pillar to post,and the mistake was done by the cashier who did not know about the procedure of selling iTunes cards and it's been months and I haven't received any feedback from the store.