None are correct. No one understands you yet. We still don't understand you.

I disagree with shenme xiao shenme. "still no one understands you." works fine, though the punctuation is wrong. For example: Hans Bethe: I don't see why I should have to explain this to the politicians again. I've been before their committee a hundred times! Random bureaucrat: Still, no one understands you. You should try again. In this context what comes after “still” is more of an explanation than an expression of time. You could have a sentence with, “We've waited an hour and they still aren't here.” “Still” in that sentence would be expressing time. I agree that “Still” as time doesn't work here, but there's nothing grammatically wrong with “Still, no one understands you” and it can be used in some reasonable context. Hope this helps!