Several years ago a seller sold some expensive cognac or bourbon and opened a dispute.

When the seller had the item returned they had replaced the contents with a cheap whiskey and received a refund.

I would call PayPal and explain buyer did not respond to request of photo's and they haven't returned the item.

Also mention you know of a scenario where  buyer has changed the contents of the bottle.

PayPal are usually very good at taking on information.