Apart from all the vitriol that your post engendered, I am trying to figure out what exactly happened. From what I can decipher, you sent the cables to the third party recipient in SoCal without having received payment in advance. That's where you made your tactical error. It is normal in these transactions for the buyer to trust the seller by paying in advance of shipment. Obviously, all ways of doing such a transaction have pitfalls, if the buyer and seller are not honorable to begin with, but you have a reason to expect payment in advance of shipment, based on past practice on this and other similar websites and assuming you are a registered member on Audiogon. (Your registering on Audiogon is at least a fig leaf that should make you, as seller, trustworthy, because the buyer can report you if you do not fulfill your part of the bargain.) So the take home lesson is get paid before shipping (and register on Agon, if you have not done so already). Not "Thai people are dishonest" (or thoughts to that effect).
It's almost a separate discussion, but if you sent the cables by UPS and asked for a signature, then UPS is the responsible party for either confirming the cables were lost or that they were delivered and signed for. You don't mention that part of the story. Trying to get money out of UPS is like..... any number of other impossibilities.