And could you post the seller's eBay handle as well if you're advising people to avoid him?

I'm not a moderator, so maybe I'm reading the rules too narrowly, but I don't see anything that would prohibit posting factual details about a transaction, including the seller's name/eBay ID (physical and email address aren't permitted, of course). The rules prohibit "defamatory" posts but I think a statement has to be false to be defamatory.

Of course the OP is entitled to post as much or as little information as he chooses (consistent with the pinside rules), and the easiest way to avoid further trouble from the seller may be to say little or nothing, even if the seller was in the wrong. It's just that a post like this isn't likely to be spotted by someone considering doing business with this seller in the future -- I would imagine a future buyer searching for the seller's name/eBay ID, but probably not his hometown.

I'd be interested in some clarification here. Is there a general policy not to post details about bad transactions (i.e. only "good feedback" is permitted on pinside)? I've read enough warnings/bad reviews to think that it's fine to post unflattering, but factually based, reports on trades/sales. But I've only been using this site for six months so maybe I've got it wrong.

You might consider reporting this to eBay. As I understand it they don't like people using their service to advertise but then conducting the sale off-line to avoid paying fees. Won't get you your money back but could lead eBay to stop doing business with this seller.

Be sure to save all your communications with him (I'd also recommend doing screen captures of the eBay listing if you haven't already) so you can show those to your credit card co. when they ask for evidence.

Post some pics! (or at least details).