"Concealed Damage" and FedEx Claims

After several happy years of buying and selling on AudiogoN, I'm in the middle of my first FedEx claims process. The item in question is a Copland CD player shipped FedEx Ground from Boston to Los Angeles with a FedEx "declared value" equal to the asking (and selling) price on AudiogoN. The original shipping box, original inner packing, and thirty pound player arrived with "no visible damage to contents," but the buyer reports that the player does not recognize a CD in the drawer and will not play it. I've filed a claim, but there now appear to be two problems: One, the buyer was out of town when the unit arrived (it was delivered to the mailroom of his work address), so the 15 day limit on reporting "concealed damage" had passed by the time he opened the box and figured out the unit did not work properly. Two, when FedEx came to inspect the damaged player they looked only at the shipping box and the exterior of the player. These were in excellent condition. They did NOT test the unit to see that it no longer worked properly and I am told that they have NO intention to do so. I found this a bit troubling and have now asked four different operators at FedEx claims how they can determined "concealed damage" on a CD player without ever attempting to play a CD. My uninformed thinking is that FedEx has no intention of allowing the claim (because of the 15 day limit on reporting damage), so there was no reason to inspect for anything other than visible damage (where the reporting deadline for a claim is nine months). Questions for the group: Have YOU had any experience with "concealed damage" and the FedEx claims process? Have YOU had any experience with FedEx and its 15 day limit on reporting "concealed damage." And, most importantly, what would YOU do as an AudiogoN seller in the event that FedEx denies the claim? Thank you one and all.