主因是使用了 non-consumable products，接著每次都收到一模模一樣樣的回應：
We found that your app offers In-App Purchase(s) that can be restored but does not include the required "Restore" feature to allow users to restore the previously purchased In-App Purchase(s), as specified in the Hosting Non-Consumable In-App Purchases section of the iTunes Connect Developer Guide:
"Users purchase non-consumable products only once, so if you host your own non-consumables, you need to provide a way for users to restore them. (You implement the restoreCompletedTransactions method in Store Kit to do so)."
To restore previously purchased In-App Purchase products, it would be appropriate to provide a "Restore" button and initiate the restore process when the "Restore" button is tapped by the user.
For more information on restoring In-App Purchases, see the section, Restoring Transactions, in the In-App Purchase Programming Guide.
A screenshot has been attached for your reference.
直到測試幾番後，終於搞懂他們在想什麼，也就是 non-consumable IAP products 必須提供類似 Restore button 才行，也不是沒實作，而是購買後才顯示出來，第一次還沒購買時，並不會顯示 Restore 字樣，就這樣一直調整 IAP 流程，每次調整都還是收到這樣的回應，直到把 non-consumable IAP products 一開始就加上 Restore button 時才通過。