Archie in the above post says: "What if the seller says he sent the package (but didn't)?
If it was not insured, there is no proof that a package was sent."

I don't know what to say about that, other than a Certificate of Mailing form............ But I always wondered about this wrinkle. I never saw it discussed before:
Say something is sent COD or using an escrow agent (who holds money till the deal is completed). What if an actual package was sent and received, but the buyer claims it arrived empty or with something else worthless inside, and the seller denies it !! What happens in a case like that?
Robert