Unable to purchase gems

[Banquo]

I tried to purchase gems yesterday but the purchase did not go through. When I try again, I get a message "The in app purchase has already been paid for and will be restored", and the game hangs. I waited for 30 minutes and then tried again with the same result. Can you either complete the purchase or cancel it, please.

[admin]

This sounds like something went wrong on the iTunes purchase flow (corrupted purchase). You may need to contact iTunes customer support and ask them to clear out your stuck purchase so you can purchase again, and issue you any refund if they actually charged you for the purchase.

These are couple links I found for reporting iTunes issues that might get where you need.
https://support.apple.com/en-us/HT204084
https://www.apple.com/emea/support/itunes/contact.html