The PM system has a maximum number of emails then they bounce - or rather they are black-holed so there is no acceptably certain way of knowing that someone has actually received a PM via YBW.

You don't say whether you have written a letter, snail mail, maybe even recorded or signed for? If you have their surname and address, have you checked directories for their phone number? BT has a free online service for UK phones but people can be ex-directory.

From what you say, you are not going to be financially embarrassed by this loss but if you falsely accuse someone of a criminal act it could have serious consequences for the accused and for you, if it is a false accusation. Maybe there is some genuine reason - you don't even state whether the goods were signed-for?

So, I suggest that before you name him you try to phone him, write to him and then raise this with the forum admin before actually naming him.

I understand that you are very angry, but are the possible consequences worth the 38 quid?