I bought something on the App Store and my iTunes credit is gone but I don't have the receipt?

I recently bought Sven goblins vs gnomes pack on a game called hearthstone on my iPhone. The $10 was deducte from my iTunes credit, but I have not received the packs and I have not been emailed a receipt like I normally do. It has been about an hour since the purchase. Did I get ripped off, or should I just wait?

You should have received the card packs instantly within the game. Go to the open packs screen and if they aren't there then contact Blizzard support for help.