Thank you all for you answears...
keeprolling - I know you're there I appreciate.But how we use to say by these sides "one swallow does not make spring" (directly translated from google )

sophiesmom - I can't really report the people who cheated... I'm the outsider, and almost everyone knew. When I tried to bring the topic today anyone whom I talked about it was upstep or even really listen to me. Almost everyone knew, and as nobody wants to talk about it, I don't have a source to know even who where the ones who did it in the first place. I will go trhough hell then.

Orchidlotus - thanks for sharing your story. It made me realize that is not on my little country, on this side of globe, that students do this kind of things... I hear so many stories like this...grrr