Resignation Not accepted - eligible to send him a legal notice during my notice period?

I am currently working in Chandigarh in IT company and i Have recently selected in another IT company. I have send a resignation email to Boss, but he was not accepting my resignation ( On Phone conversation). He said , he will relieve me on Month of June, but i have to join other company by April 1,2018.
In my resignation email, i have mentioned that i will work for 2 month as per my notice period. But he is not acknowledging my resignation letter.
My boss is not present in India, so i have also tried to talk to his brother but he is also not accepting my resignation and also said do whatever action you want to take.
So am I eligible to send him a legal notice during my notice period tenure or i have to wait till my last working Day?
Do i have to consult a lawyer or Have to complaint against him in labor Commissioner office?

This needs careful handling.
If you are following the offer letter conditions, your company cannot stop your exit.
Put up a letter in writing to HR and copy to your boss and obtain an acknowledgement .Clearly mention last date of working and refer to the appointment order/offer letter which governs your relationship with the company.
Sound out your new company that due to your current employer acting diffiuclt there may be difficulties in getting relieving letter.This decision to inform new employer must be done very thoughtfully and carefully as you have to judge how your new employer will take this kind of news.
Legal resort is to be taken as a last measure to enable your timely release from company.
Labour officer cannot help in such disputes.