Former employer released me from work early but did not pay for notice period

Hi There, I worked with a consulting firm in Mumbai during 2012-2014 and I left the job in July 2014. This employer had a policy of 30 day notice period (from either side). After securing a better job in another company I had resigned from my position by sending a resignation letter via email. Surprisingly the company immediately excepted my resignation and released me on the very same day (it was a willful resignation initiated from my side. No disciplinary action or forced termination by employer), however they have not paid me for a 30 day notice period which I suppose they should have. So I have below questions: (1) Is there any time frame within which I should have/ could initiate action against the company? I.e. Am I still eligible to take action against the company considering the fact that its already been almost 3.6 years since I left the employer.. (2) If I am still eligible - How do I get the company to pay me for the 30 day notice period? Thank you in advance for answering the questions.