Curiously I have twice been scammed on ebay (and once I bought a guitar that I believe the seller genuinely did not know had a stripped trussrod and he and I reached agreement about varying the price) - one I resolved as above and one I lost the £20. Actually another time I bought a 12-string that was considerably worse than I expected it to be: I was execting a crap but usable guitar but this one was both untunable (intonation WAY off) and unplayable (probably needs neck set, might get away with flattening table and planing bridge) but the seller was a junk shop not a musician and might have been telling the truth when it said it didn't know.

In both scam cases the seller had a chinese name and was a fraudulently created identity.

I'd say not to buy from chinese sources.

Normally I demand the other party's name and address, and check it with the electoral roll. If it doesn't match, I'm gone.