1. How were you appointed in the said Company?
2. When you had joined the Company, did you receive any appointment letter? If not then who told you to join them? What is the document through which you had joined them? You are silent on this important matter,
3. Actually if you have joined them where they have forgotten to issue you appointment letter detailing the terms of the appointment, then it is their mistake for which you are trying to take benifit of,
4. You can send them a legal notice askinbg to asking them to issue you a relieving letter,
5. If they refuse, you can file a damage suit in addition to complaining the matter to the labour commissioner,
6. Try to settle the matter amicably, if possible, since your emloyer can delay issuing the release order on some ground or other for want of which you will not be able to join your new company,
7. Moreover, if your new company comes to know that you have taken advantage of the mistake of your earlier company and left without giving notice, they may become reluctant to employ you,
8. Handle the matter carefully.