Ineligible for reimbursement?

Sent in around 100 units on one of my private label products. They were in perfect condition when shipped. I noticed 47 were missing from my inventory so contacted Amazon support.

When I appealed, they said the following:

"As per our policy, these products are not eligible for reimbursement. xxxxxxx - These disposal event with disposition {DEFECTIVE} is not eligible for reimbursement"

There was absolutely nothing wrong with these. Certainly not defective. Although I have tried to chase it, I keep hitting dead ends. Anyone had this before? What can I do?