Central Board Of Secondary Education [CBSE] — Freezing the documents

I'm Aishwarya I have worked in cbse school, national model school Coimbatore .I signed a bond there for 2years but I asked while signing that document if emergency shall I leave they said yes. they didn't gave copy of that nor any joining letter.the salary also which we are receiving isn't having any proof that it is from school . There is no proper respect for teachers. No staff rooms nor chairs for teachers in class rooma such an torture school.they didn't gave salary also properly which I signed for .due to Emergency financial crises I submitted my resignation they took that and after a week principal is saying me to gave the fine amount of 3months salary which is not possible at my situation now ..and if I give the amount only they will give my original certificates they said .it's my career please do the needful.