Have you considered that the items were damaged by rain or mishandling in transit???

As the buyer has not informed you of the problem you immediately assume fraud.  You have also stated they are new with only 4 feedback.

Lots of banks cover you for receiving damaged items or items breaking within a certain period of time after purchase.  I know mine does.

The purchaser may not have a PP account and paid using a credit card without logging in to PayPal.  If this is the case they would claim through the CC provider and not PP.