why do guys leaved us hangging without saying anything? am i that ugly?

A good question.
There trouble is, the number of potential reasons is enormous.
And unfortunately, unless they come back and explain, you'll never know what that individual's reason is.
Its a disappointing situation, I know - been there my fair share of times, and not just on here. With personal friends, too.
Its just something that some people do that one has to simply shrug off, as there really are no other options.
As for the question of appearance, I can say that you are not ugly by objective standards, no.
I will say no more than that, since it goes into subjective territory, and such doesn't do well to answer such questions, but my prior statement stands.

don't know yet. but i am willing to find out by chatting with u

Depends on individuals.....some cos of fear of rejection...some don't want to commit oneself,i suppose.....