I recently went through something similar with a bike that sold too cheap AND had too cheap shipping. I knew better to bid but there was so little money involved, less than $40, I figured it was worth the gamble. After a week I got a reply to an email saying she was out of town on an emergency. Then after another week and having to call her I got an email with a ton of excuses all wrapped up in one... ebay account got hacked, shipped the bike ups and it came back 2 days later all shredded up, ect. Took me 20 more days for the Paypal Dispute to play out before I got my money back (voluntarily) in 2 separate payments of $20.
I would say there's no way you're going to get the bikes. Turn him in to ebay.
If you would like some *expert* opinions, check out the Usenet newsgroup alt.marketing.online.ebay . They handle this sort of question all the time and there are similar problems to yours already posted.