Hi Vishwas, please read through the contents of your appointment letter once thoroughly and see what is the notice period provided in there both sides, employer and employee and in both events, termination or resignation.
Since, you mentioned that you wish to resign and your company is not issuing a reliving letter, please also let us know what was the mode of tenderence of the resignation by you, whether the same was served by hand or by e mail, if the same was served by an e mail, whether the read receipt was attached to the same or not.
If the same was sent by an e mail and there is only a verbal refusal to issue reliving letter, then you can mark another mail on the same subject, copying the MD regarding your requirement viz., relieving letter, (also keep a copy on your personal e mail ID), still your employer refuses, suggest to take the same up with in the Court, I tend to disagree with the views of Mr. Vasudevan, as I am not sure whether the matter or employment would fall within the juridiction of the district labor authorities or not, yes, if your employment terms fall in the category of workman, sure without second thought, your employment terms should fall within the jurisdiction of labour court.
trust this suffices.