Notice period in job

In my appointment letter it's written��if you desire to leave the service of the college at any time you will have to submit to tha management three months notice in written. However management shall be at liberty to accept the resignation at any time even before the expiry of the notice period without any payment for the remaining period. Upon termination of your employment you shall immediately return all documents kits � Now they have refused to accept my resignation and have told me that they will show me absconded. They are not willing to give me no dues certificate. Kindly tell me if I give them still stat resignation, can they send me notice regarding giving them compensation for 3 months in the form of my 3 months salary? And what else they can do against me�.. Due to health issues of my parents I have to leave this job and management is not willing to do compromise now