Purchases are normally processed straight away, but they may take a while longer sometimes. If the purchase is delayed it may be because it is still being processed. Don't try to place the order again, since you're likely to receive your purchase any time.
If 24 hours go by and you don't receive the purchase, please contact the Support team at iTunes. Apple processes all payments made in the game. You can contact them here.
If you made the purchase through Google and you haven't received it after 24 hours, contact us and send us a screenshot of the purchase's invoice. Make sure that the screenshot has all the information, including the transaction number.