How to get full and final settlement and relieving letter

Dear sir, ,I was working in a “Mahindra rural housing finance ltd “company from 3.3 years at Nalgonda branch. The company is registered in Mumbai.  I had given proper resignation through email to my reporting manager cc hr department without specifying my last date of working. They have accepted my resignation and had given the last working date which is 1 calendar month from the resignation date. I was served my notice period ( 1 month).i was releaved on 18/03/2016. still now I am not receive my final & full sattlement & Releaving letter. Kindly advice me sir.