which later i found out ebay never promote western union as a method of payment
Hindsight is always 20/20 my friend.
Anyway, did you try to use the Money Transfer Control Number? This apparently tracks money transfers via Western Union.

I gotta say you're pretty much SOL. Problem is, I have hard time feeling too much sympathy, when right on Western Union's website (on the main page under the bold title "Protect Yourself From Fraud") is this:
Because we care about consumers, Western Union urges you to protect yourself from fraud by considering the following:
-Never send money to a stranger using a money transfer service.
-Beware of deals or opportunities that seem too good to be true.
-Don’t use money transfer services to pay for things like online auction purchases.
-Never send money to pay for taxes or fees on foreign lottery winnings
Sorry bud, this is one of those situations where all you had to do was yield a little caution & the outcome would have been completely different.