Well, sometimes, and I've had this happen before, 
the e-mail of the person won't work, or they are 
sending you messages, but you are not getting 
them because their or your e-mail is not working. 
This could be the case, or this person might have 
had an accident or be well...dead. Ok, that is 
the extreme-but, there is something you can do. 
Get a hold of their contact information and give 
them a call on the phone...or...

Well, once I was getting e-mails from a winning 
bidder but they would not get mine, they gave me 
their address so I sent a priority letter to them 
telling them I'm sending them e-mails but to give 
me anoter e-mail address because darn it, yes it 
was frustrating-they kept waiting for a reply and 
I was giving them so many e-mails. Finaly, they 
got my e-mails and such, so it worked out well.

Just, well, if their negative feedback is 
something along the lines they won't sell, then 
well...like the others say they backed out of the 
auction. Sometimes as well f they have like so 
many positives the negative seem like lost in 
them well...check to see how many positives they 
have lined up with the negatives. Say they have a 
thousand positive and two negative. It would tell 
me they still are ligit, because they might have 
run into a mean ol' person or something... Means 
they might have had trouble with two people who 
were asses or something and did that to them. 
I've had that happen-some under-age kid was 
threatening me to leave negative feedback because 
I never got their payment for some small item. 
Now, yesh-who would ruin their rep of a $8.00 
item? In that case, I warned them I would contact 
Ebay and let them know he was going to do that 
and was REALLY under-age...so they let it drop. 
Well, them beng like 14 years old... Some people 
can be vicious too, so their Ebay negatives, read 
them and see why or contact those people and see 
how their attitude is. After doing all this, 
requesting their contact info. and still no 
answer, ask Ebay for help. Sure they would. Isn't 
winning a binding contract? If the seller tells 
you they won't sell...can't they take legal 
action or something? Man, if it was a dream cel 
like a Kouji one... Darn it-I'd take the seller 
to court for it! Hehehe, but that's me...

Anyway, hope your delima is solved!