When were all of your materials in to Case? They do things very quickly. I think they started giving out interviews in like July maybe, so if your app wasn't in early, it doesn't mean you aren't a good candidate, but I'm pretty sure by now their interviews for the year are all filled up or almost filled up. It's unfortunate, but I guess that's kinda how the rolling admissions process works.
Each school starts looking at things at different times. Case is probably one of the earliest, and I know some schools just started giving out interviews recently or will be soon. Don't get too worried!