Our app is offering auto-renewable subscription products only. One of our customers told us that she was having a problem to purchase a monthly auto-renewable subscription in our app.
In our server database, we found the customer's transaction receipt's payload which was used to post to the Apple's receipt verification API (https://buy.itunes.apple.com/verifyReceipt). Then we tried to post the receipt's payload to the API. After that, in the information we received from the Apple through the API we found out that the key of "in_app" in the "receipt" is an empty array, indicating that there was no product in the receipt and causing the customer receiving the purchase error in the app from our server. Most of our customers were able to purchase the subscription, so this was a rare case.
The customer told us that she was never charged by the Appe store after the multiple attempts she had made to purchase the subscription product, meaning that she did not purchase the subscription product successfully.
Our questions are:
1) Is it possible a receipt's payload being generated without a successful purchase of an auto-renewable subscription product?
2) How is the receipt's payload generated and sent to our server?
Please advise.
Thank you.