Forecable resignation taken by IT Company

I am worked with the company almost 7 Years. Senior Management Team to safe guard their Pay, decided that 40% of the employees are kept in under non-performers and for those no Variable Pay and increments was given. Senior Management Team members conducted the sessions and informed the members that Company will give you to prove through Task (Development Plan) which has to be completed with in 6 Weeks of Time with Three Reviews. If failed to deliver, employee can be terminated. Task has been given and sucussfully completed by the most of the employees. Process is through system and review acceptance also through system. 1st reveiw went on well for all the employees. But Senior Management has different view and decided to retrench employees. So, freezed the system and conducted 3rd review for name sake and asked to resign otherwise termination. In my case, HR informed that DP was failed and resign otherwise you will be terminated. Requested the HR keep in my AGE 55 and consider better package or allow me to continue to get other Job. HR informed me that there no such provision and asked me to resign or accept termination. Requested better package which has been rejected. Informed that terminate and let me go the for Legal Justice. Immediately informed me that 3 month Notice Pay will be paid. Taken a call and accepted and resigned. Once the money deposited in my Account, sent a mail requesting to pay additional compensation keep in mind that my Age and Company Brand. As I know, company will not allow any un-ethical practices which doing by local senior management team Responded VP, HR stating that my termination has been done purly based on non-perfermance and said there no un-ethical practices. Provided examples and information, how the appriasal system is misused and asked the employees to sent out. VP, HR sheduled face to face discussion and decide on further Action from both the sides. In addition to that I would like to inform that handon work force are terminating and again recruiting the new employees to continue the project by providing Training. I want to know that can I knock the doors of Labour Department and Civil court on my retrenchment at the age of 55 without honoring my request. My next step is If, issue not resolved here, sent a mail to Head Office and request for More compensation and If, rejected in Head Office, request Corporate Office. In fact, I am hopefull corporate will consider my request. If not, move to Legal Authorities. Thanks Atchutuni