Years ago I had s similar experience. I had pre-ordered some items and sort of forgot about them when I moved a mile away. The package was delivered by UPS and signed for my my former nextdoor neighbor, according to UPS records. I went to the neighbor and they denied that (not sure I believe them) and UPS said there was nothing they could do since it was delivered and signed for.

The problem is if the package is not specifically insured, they drop it off by the mailbox, or door and do not get an actual signature, only an "implied" signature. They take no repsonsiblity. Insurance is the only solution.

Since you used Paypal, you may want to contact them and see if buyer protection was in place and if it can be of help.