safe-t claim denied

We had an order where the customer first requested a return, the reason for the return was not as described, and then the item was not returned to us. Amazon refunded the customer. We can't contact the customer. We are enrolled in the CSBA program and applied for a Safe-t claim, which was denied, the reason for denial was： The issue you reported is not covered by the CSBA program.

How can we make a successful complaint and get the money back to us. Need Help!!!

SAFE-T claim ID：55410-36536-1451762