Forky and Spoony (there are two people behind 
this commericial fancel painting service) have a 
website here:

http://www.geocities.com/forkysanime/

And you can send personal emails to them at the 
following two addresses:

forkysanime@yahoo.com
forkysanime@gundamwing.net 

I think people have tried contacting eBay in the 
past, and obviously that didn't go anywhere. So 
maybe if everyone who doesn't appreciate their 
bad eBay practices contact them induvidually and 
ask (politely but firmly) that they only paint on 
commission and stop jacking others' cel scans, it 
might have more of an effect.

Best,
~ keeper :)