I think I'd be booking a flight to Rybski's hometown if I were in the OPs shoes. And I'm no tough guy. I would want however to confront him face to face. We're not talking a couple of hundred dollars here, we're talking thousands. And if everything the OP is stating is true, which I believe it is since Rybski hasn't come around with a counter story, then this is a very big deal. And it makes absolutely no sense that he's not either returning him money, or sending him a bass. If it were me, I'd be absolutely livid. I almost am NOT being in his shoes. But I'm not losing any sleep, and I'm only thinking about it when this thread pops up

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He was robbed. Period. And he knows who robbed him.