This story may have some relevance to the current situation:
Sometime back in 2004, I was the high bidder on a set of factory alloy wheels/rims for a '93 Lincoln Mark VIII. Payment was sent off, and acknowledged. I waited a month, two months, three months, nothing shows up (large/heavy boxes tend to travel really slow across the US/Canada border). I tried file a complaint with eBay, but eBay stated that the time period for starting the dispute process was over (45 day limit. later extended, I think). Same story with Paypal. Figured that I was out $400.00 or so.
A few days later, saw an online news article that mentioned fraud.org. Logged onto fraud.org, and was able to make a complaint there. On that site, they also suggested that going to the US Postal Inspector's site (somewhere on the USPS.com website; don't remember where exactly) and lodging a complaint there. Evidently the seller was not the most upstanding citizen, and my complaint may have triggered something, because they got back to me 3-4 days later via email, and requested that I provide details and any supporting documentation. Wrote up the story as I saw it, and provided screen shots of the ebay listing and the Paypal reciepts to prove payment. They prosecuted the case, I got my wheels/rims after about 5 months, the seller got 6 months for Interstate Mail Fraud, along with a federal criminal conviction.
I don't know if the US Postal Inspector will take on your case, but you might want to try. You may want to also lodge a complaint with fraud.org. From what I read on the US Postal Inspector's site, they have jurisdiction over internet sales as well as regular mail/mail order sales.
Kostas