They has bumped up their ratings through purchasing.
Buy Smart check the buyers ratings.
Any negative feedback in the last 6 months needs investigation, check recent ratings box.
The feedback speaks for itselves.
Based just on this evidence I would walk away.
Also for future reference paypal only covers you for 30days. So if I were you on large purchases use your credit card as they have more clout.
another thought is to become an ebay vero member. You should easily be able to get him,her or them booted, worth investagation.
If all else fails try TV. They like these stories and might get ebay to react if the above has failed.
I agree a very shady character "Buyers Beware" ..... Of course if they can do it to you and get away with it whats stopping you or a friend doing the same back on them (recouping the money).....(oops was I thinking out loud)