i have been dealing with this same issue for a while now, and there are some catches....
I had a cue arrive all dinged up, and the box was also damaged. I contacted the USPS and they told me I needed to get with the seller, pay to ship the cue back, and that he had to file the claim. So I took a bunch of photos, and mailed it back.
The seller got it back and attempted to file a claim, and they would reimburse him for the insured value, and he could refund me, but they would keep the cue. Instead the seller and I agreed to get the maker to refinish it, and he would send it out as soon as it was done..... that was 6 mos ago.....
so, bottom line... Only the shipper can file the claim.
and let me know how it works out....
D