A-Z claim for half returned item

A-Z claim issued where only 1 of 2 boxes have been returned.

We have provided the outbound tracking number that shows 2 of 2 packages delivered, customer returned 1 box with Evri return label then raised an A-Z claim, we appealed with Amazon but the refunded in full stating 'we determined that the merchandise for the order was correctly returned and you have received the return.'

We have stated that we need the full return to issue the refund, and that half a return is useless to us, and now the customer has got half of the item (Which is very functional on its own) for free?

@Sarah_Amzn@Roberto_Amazon help please!!