I just received my supposed 2GB card from an Ebay Hong Kong seller too. Guess what? It was marked with a little sticker that said "2GB" but my 770 only reads it as a 1GB. I had to format it in order for it not to be greyed out in the file manager.

I actually did read a few feedbacks on this Ebay seller saying he sent them a 1GB instead of a 2GB but his overall feedback rating is 98.3 with over 9000 sales. He goes by the name of "wholesaleoffer" on Ebay. I've emailed him to see what he intends to do about the bogus 2GB card, but, I'm sure I'll not get any resolution. BTW, it took a month to receive it (I live in Colorado).
Live and learn!
Neil