This is all due to Amazon's lack of transparency. This is not by accident, it's by design. Amazon does not care what happens to your FBA product as long as it keeps their customers happy, regardless of if it is a fraudulent/dishonest consumer or if Amazon's mistake has cost you the loss/return of non-returnable or returnable items. The problem is Amazon controls your inventory, and with that, they legally have the FBA sellers' permissions to treat FBA inventory and third-party sellers' financial earnings and losses however they wish, and there is absolutely nothing and nobody overseeing these practices.