Complaint agianst college management

Hi, I am ravi from working in an engineering college. recently my college management asked me to give resignation through HOD. it was in april 20 2018.recently AICTE changed the faculty student ratio from 1:15 to 1:20. this has impacted all the private engineering colleges and they started terminated faculty.AICTE has issued an order that no faculty shall be terminated or forced to resign, unless the faculty resign on his own. my HOD constantly calling and nagging to resign by giving resignation letter. he also told that if i don't give resignation letter then i won't get my april salary and further my salary will be stopped. also the office assistant used to call me and she to nagging around to give resigntion. I have recorded all their conversations with me. the management demanded me to get relieved by april month end. according to my appointment letter 3 months notice period is to be served if i resign or they terminate me. As such I wrote a request letter to the management to give me three months time. i also mentioned in the letter about Instructions from the HOD to me regarding resignation.initially the management denied my request and the office staff informed me to relieve by month end. then i kept quit till month end and they called me and told the management gave me time till June end. but according to my appointment letter 3 months time is to be given i.e up to 20/7/2018.they removed my name in the attendance register for July month and constantly informing through DTP and office assistant to submit NO Dues and take relieving letter. when i asked the office staff , she said they are considering the request letter as resignation letter.the management has never given anything in writing and they communicating with me through other staff that to verbally. i feel like i can file a case on two issues 1) Forcing me to resign from my services 2) relieving before 3 months notice period as per appointment order the mangement is holding my certificates with them. iam going to the college veryday even they removed my name from register. iam giving biometric attendance everyday which is controlled my parent university. can anybody advice me legally. regards ravi