Legal Action Against Employer For Not Giving Relieving Letter On Completion Of Notice Period

Dear All,
I have given my resignation to my current employer on 6-02-2015 through email. I am working here from last 2 years and now I want to join a new organisation. In my offer letter of current company 30 days of notice period is mentioned. I have mention the last working day on 5-03-2015 in my email. But my current employer will not ready to accept my resignation and said that you have to serve a notice period of 3 months after my resignation.
Please help me on this and let me know what I can do.
Thanks

Assuming that you are working in Delhi, you are governed by Delhi Shops and Establishment Act. Under section 30 of it you have to give 30 days notice or salary in lieu thereof. Better give salary and get relieving through inspector under the Act.
Thanks
Sushil

Thanks for reply. If current employer will not ready to give reliving letter after serving the whole notice period, then where I file a case and what are documents will be needed for it.

Firstly Pursue with the inspector under that Act. Then in that case send registered letter to the employee to do Fnf settlement and give relieving letter. But after notice period you will be deemed to have been relieved. If the employer does not issue the letter, then make a formal complaint to the inspector under that Act.
Thanks
Sushil

Here, I am attaching a screen shot of the terms signed by me on the offer letter.
In the section 15: I have agreed that the employer reserves the right to amend the rules anytime. Would that bound me to serve the notice period of 90 days ???
However, in section 17: There is a condition to serve 30 days of notice period in the training period. And the training period was for one year.
Is there anyway I can have a legal point for me not serving 90 days of notice period?

Your employer cannot contract out contrary to the Delhi Shops and Establishment Act unless the terms are more beneficial to employee. So irrespective of rules the company, the employer will be bound by 30 days notice period and you would be.
Thanks
Sushil

Hi, I have resigned with my current employer and served a notice period of 3months in full. on the last working day I also had put a mail for final sign off and boss replied all the best. He has not approved my final signoff and saying excuses there is some network issues. I want to initiate legal action against my boss. Kindly advise me in this