It can take up to 24 hours between the purchase and the gems to update in the game as our system needs to receive the confirmation from iTunes.

If you still haven't received the gems after this amount of time, please check your mail for the iTunes receipt, take a screenshot and contact us by sending a request attaching the image.

Failing this you can access your iTunes Store account and go to the Purchase History section to get the same information.
Take a screenshot of the Purchase detailed Information when you click the grey arrow for the purchase in question.

Note that if your purchase process was interrupted by a phone call, low battery, message etc., you’re NOT supposed to be charged. You just need to start the purchase process again.

Without this information, we cannot confirm that this payment comes from you directly and you will need to request a refund directly from Apple themselves as they are in control of all payments.

You can contact them directly from here:

http://www.apple.com/support/contact/