When you purchase a package in the Cash Store, the packs' content is delivered instantly. However, delays may occur, this just means that the purchase is still being processed by iTunes App Store.
Sometimes, connectivity issues could introduce delays. You can try restarting the game, and any pending purchase will be processed at that time.
If you still haven't received a purchase made more than 24 hours ago, please contact iTunes Support. Apple processes all payments made toward the game. You can also contact us, and provide the corresponding purchase receipt.