Read an article last year about how common that fake silk problem is, it's basically plastic made to look shiny. Totally feel your pain, that's such a letdown. There's a place called Fine Fabrics off of Harry Hines that has a huge selection you can actually touch. The staff is pretty helpful if you tell them what happened to you. I'd avoid the online swatch thing for anything that needs to feel a certain way now.
Ugh, it's the worst when that happens. I had a whole batch of lining material that felt like cheap plastic wrap, totally ruined the drape. Makes you want to just give up on the whole thing. Margaret's right about touching stuff in person, it's the only way to be sure. That fake shine is such a trap.