Oh ok. I thought there was a bug or something.
Unfortunately we can't really go deeper than that. With that functionality you need to write your purchase in swift/objective c. We're not in the position to write code for our users, as this can get very problematic very quickly.
If you had some in-app purchase code or something started we'd be happy to look at it and assist you. But can't write the entire logic.
Basically you need to learn how to make an in-app purchase in XCode, then use that bit of code @Hamed shared before to tell hyperPad that purchase has been made.
But I'd start with something easier. Try to send/receive a simple value between objective C first. Then work your way up to an entire purchase system.