It is only a legal agreement, I believe, if the item was listed at auction (you don't mention if that's the case). Regardless, if this story is true, tell him you want to contact the other guy to verify. If this person is on the up'n'up, they should offer to reimburse you any expenses you've incurred in this run-around so far, but if not, tell them you expect them to send you payment to cover the cost of stopping yours if that applies. Make it clear that this is an imperative when it comes to the feedback you will leave, and what you will tell Audiogon about his member friend. And get yourself a sincere apology! These idiots should be paying you interest for all this time.
If the first guy will not give up his "buddy", BTW, persue the line of action I suggested before. In fact, do that anyway! He hasn't looked out for you in the least, and could still be conning you even if his so-called friend is unaware. Who is this guy? If he had ever intended to send it to you at all, you would have had it by now. Why the month of no action? Either his accomplice changed his mind before he allegedly went on vacation and thought you wouldn't miss your money while he lied around in the sun, or he was stringing you along for a nit-wit with seller's remorse - or the whole thing's a sham. Do not let the pressure off for a second. Best of luck!