How to release original documents from employer

Hi, I am currenty working as a Assistant Professor in an institute in Bangalore. An institute under Bangalore university has asked me to submit my original documents to get job. and as per the requirement i submitted it. they have mentioned the same in the appointment order as well stating that they will release my documents after a minimum service of 1.5 years plus two months notice period or else i have to give them two months salary to get back my documents if i leave in between. Now after a week of my joining i found difficulty in managing class due to lot of boys students. because of which i have undergone lot of mental pressure and nervousness and my health has also suffered because of it. I went to the college principal stating the above issue. expressing that i may not be able to continue like this. and for the fear of penalty i may continue but will not benefit students or the institute. So i asked them for a mutual conclusion. But they have not accepted this and asked me give penalty in lieu of my documents. Meanwhile students also came to principal expressing that they are not able to understand in the class. Now the institute neither are permitting me to continue nor are they ready to give my documents without serving the penalty. i dont want to give penalty. kindly please suggest me what should done now. Thanks.