BIlling Issue: game card code already used.

Hello there,

earlier this week I had purchased a WOW game card, from an EB Games store. The next day I scratched the card...and went to add the game card to my account, and i was told that the game card was already used.

I contacted the billing department and gave them the game card code, and the 7 digit side number. They told me that they would look into it but I have not heard anything back yet, and my next billing date is on March 25th, and the credit-card attached to the account can not be used at the moment(which is why i got the game card).
Just would like to know if I have to run out on Saturday and buy another card...

Any word on this would be great,

Thanks alot.