How do I cancel payment for an app?

This may vary from store to store; however, Apple (via iTunes) sends a virtual receipt to your registered e-mail. On that receipt there is a "Report a problem" link. If you deleted the e-mail, then you can look at your Purchase History in iTunes and click the "Report a problem" link next to the name of the purchase. If you don't have iTunes, then you can report problems at: reportaproblem.Apple.comTo iterate additional (adequate) information: Apple doesn't support cancellation of app purchases, and they're intermediately strict when it comes to refunds. You will need a reason for your refund if on an Apple device. As for Android, you can visit the link here: http://bit.ly/1w6DWQC to request a refund. Be sure to select "In-app purchase" from the dropdown menu when on the google Support page! You will need to specify your problem to Apple in your "Purchase Appeal."