Now this one is a toughie.  The problem is that
you waited for almost a year.  What type of
payment did you use to pay the seller?
Paypal has a buyer protection program where a
buyer can file a dispute against a seller if
he/she has been cheated.  However, I believe they
have a time limit on how long you can wait to file it.
However, if you paid with a CC, then you can file
a dispute with them.  I one time got scammed out
of $600 in products and was able to file a dispute
after 4 months with no problems except for lots of
paperwork.
If you paid with a money order/check, then the
only thing I can think of here is to file a mail
fraud charge with your police and they will
transfer the charge to the police in the person's
state (if they live in the US).  This I have never
done before, but I know of some good websites who
offer lots of help with that.

Now, if you know there is no way to get your money
back, then what I would do is pay someone to fix
the missing paint spot on your cel.  I one time
bought a cel from Yahoo Japan and that had paint
chips in it (and they didn't say it either).  This
cel I also paid a very heafty price for it.  But,
I went to a local Anime con and a cel painter
there professionally fixed it for free (you cannot
ever tell).  
But, if you are still trying to get your money
back, then don't do anything with the cel!  Then
they will have a good excuse to refuse you now.

Hope this helps.  Best of luck.

Star Phoenix