Company Not Giving Relieving Letter Even After Serving Notice

I worked for a product company in Gurgaon for around 2 years. Resigned the job and served 2 months notice. After 1.5 months through my notice period, the company offered me a promotion and salary hike. I did not accept the same in writing. I took few days time and I rejected the offer. It was almost my last day of notice. The HR said I cannot leave until they find a replacement but did not give me any tentative relieving date. So after serving my notice, I informed the HR that I will not come to office anymore as I have to join my new company.
I have my resignation mail and also the mail I sent on the last day. Now the HR is not giving me relieving letter, FnF and ESOPS that was vested during my employment.
Can I take any legal action against my employer

Yes you can. Under Shop and Establishment Act you can take action. Contact your local Labor Inspector and lodge a complaint. Also if wages less than 18000 then a case under Payment of Wages Act can also be made. Also a civil suit under Indian Contract Act can also be lodged.
Appreciate If Helpful

You may please write a letter to employer in which you narrate the details in choronological order and finally declare them that you may not be able to attend duty over and above the requirement of stipulated notice period. Finally, requesting them to issue relieving order as per the terms of employment. Such letter be sent to them by Regd Post with Ack due. They will definitely respond to you in writing. Any failure on the part of Management, you may proceed to legal action against them. The letter that you have shooted to your present employer be a valid record to prove your prospective employer that you are in right move, which may at some time acceptable to them. Regards,