Once I had UPS pick up a pair of audio speakers to be returned and I was given a receipt and that was that.
Also - one time someone I know had reel to reel master tapes damaged in shipping, he put in a claim and UPS did reimburse him.
Only Tom has any real insight on what could have gone wrong and how, and there's always the chance that the missing PD's will appear.
Sounds like a Perry Mason episode - "the case of the missing PD's."
When I was in college in Buffalo in the 70's my apartment was pretty much an open house, of course that was normal behavior in those days.
One night I went out to see The Ramones and The Dictators at the college, when I came back my '68 Fender Stratocaster was gone, missing and the door was unlocked.
This was during the winter - Buffalo, if you can imagine.
You can also imagine how pissed off I was. About a week later I'm in my apartment - my door still unlocked - and i was throwing darts at the dart board (my roommates and I tacked photos of us on the dart board as a joke) - anyway out of the blue some strange adult man walked up the stairs and walked into my apartment into the living room holding my guitar.
"Excuse me, I believe this belongs to you."
"Yeah! Wow, how did you.."
"My son broke into your apartment and stole it, it's been sitting in my backyard all week, I didn't know what it was. Believe me he's going to be punished for this."
I thought the guitar would be trashed, sitting in the freezing blizzard snow for a week.
It played OK though - then over the holidays I brought it to Gracin's, the repair shop in Long Island where I grew up, and the luthier said it's fine, didn't even need a setup.