common case if you bought from eBay and the store is from China. On my last trip to shanghai visiting my family 3 years ago, they already selling 32GB usb while the 8GB is just out in the market.
Ask refund or open case with ebay, if you're paying with paypal you're under $20 buyer protection.
one little suggestion: next time see the seller reputation, pay attention on the neutral and negative feedback and see any buyer who bought similar/same item as the one you want to buy, if none then go to first 200 positive feedback, look for the same criteria then ask them their experience with the product.
cheers
