Ouch, that sucks.
That's why if I ever buy Ayumi online I make sure they give accurate information, have a really, really postive rating, and if possible, have photos of the product. Still won't guarantee it's real, but it raises your chances of not getting duped. I've certainly found great Ayu deals on eBay.. I got Duty and LOVEppears used but in EXCELLENT (no scratches, even with the OBIs and inserts!) condition at $11 a pop from a seller in Japan.
Point being, just be careful.
Lots of people sell bootlegs and hope that the buyer won't notice -- this is especially crappy if it's someone new to jpop and they find out a while later that their copy isn't real.. some are convincing -- so you just have to keep your eyes out. It's always better to buy from a trusted place like YesAsia.