I have personally not had any problems with 
returning anything to them, if you have a receipt 
and a good reason. You should find out (if you 
don't know already) which branch store sold them 
to you via the auction site (they contribute from 
all over Japan). And see if you can track down 
the manager in the cels (celuga) section. You 
might be able to pick up the phone and dial. If 
you speak Japanese even better.