It wasn't too hard to pull off this trick with Touch ID devices - you put your finger on the home button and before it goes back to the home screen it authentic

It wasn't too hard to pull off this trick with Touch ID devices - you put your finger on the home button and before it goes back to the home screen it authenticates the purchase with your fingerprint. Apple has put some measures in place to prevent this from happening, or at least notify you immediately about the purchase if you leave the app before it's completed. Since the iPhone X with Face ID, you have to double tap the side button to authorize a purchase, so it's not so easy anymore. Fortunately, you can get a refund within 14 days, no questions asked, by going to reportaproblem.apple.com and choosing "I would like to cancel this purchase". If you're outside the EU or it's been longer than 14 days, you can try the "I would like to request a refund" option - you will be either refunded automatically or it will be sent to Apple support for review and they'll get back to you within 48 hours. I've actually had luck with refunding an app and an IAP even when someone manually reviewed it, but YMMV.