I always put return address on things I post, you can leave a additional message for the driver so if it's a female not to sign either way you keep the proof of you sending it and have proof from the driver that someone has signed for it paypal can't argue with that? Then police is the next stage I guess, if the address is near or have any links to the person who has bought it you could put up a strong fight, it would be a waste of time for the buyer but you have to have proof of postage and send it to paypal in a good time frame I would imagine.