While counterfeit flash drives are definitely a scam (they are a huge problem on sites like eBay and amazon.com), they are outside the scope of the type of scams we normally deal with here. Counterfeit flash drives are typically "real" drives--but they are typically small drives that have been reprogrammed to appear to be much larger. There are several technical sites on the internet that have instructions to help you find out the true capacity of the drives.
I can only suggest that if you paid by paypal or credit card, you file a dispute. Unfortunately, if you paid by Western Union or Moneygram, there is no hope of recovering your money.
Assuming pcfounder.com is the website you are referring to, I can say that a quick review of the site gives several red flags. I didn't see the ordering pages because I had scripts turned off, but I assume their prices were well below the normal market price for the products they advertise.
I won't go through all of the flags, but one of the biggest is related to the dates:
Established in 2001, Pcfounder Technology Industrial Co., Ltd specializes in research, manufacturing and trading computer accessories,such as CPU Processor,DDR Ram, Hard drive and Mainboard,Monitor,etc
Also contains "news" from 2009 and 2010, both of which are interesting in light of the domain registration dates:
Domain Name: PCFOUNDER.COM
Updated Date: 28-feb-2011
Creation Date: 28-feb-2011
Expiration Date: 28-feb-2012
So the website is only 2 months old, and is registered for the minimum period of one year, yet it is written to appear to be much older. Doesn't exactly inspire confidence. A few searches brings me to this site (as well as others):
http://www.sunshine-elec.com/ ( 6 months old, also registered for a single year). Compare that page to the "about us" section on pcfounder. Look familiar?
Definitely a site I personally would stay very far away from.