I'd start
here with an eBay "contact info" request to see what name/address is listed, and call the phone number that is provided. I would also call 411 to see if there are any phone #'s listed for that name in the Burbank area.
Or as mentioned earlier, you could request to pick up in person. Even if you don't intend to, it might be worth asking just to see what his reaction is. If he is reluctant to meet in person and exchange for cash, I would be very skeptical of the deal.