What options do i have if company doesn't provide my relieving letter?

Your employment rules are governed by the Employment Contract which you had signed at the time of joining the firm. Now if the same requires that a 2 month notice period has to be served before resignation, then you have to comply with the same.

You can make a representation requesting them to waive off the last 3 days, however it is at the firm's discretion to allow or reject the same. You cannot coerce the Company in any manner to allow your request and relieve you 3 days early.

You can request the other firm to let you join after three days and you can show to them that you had made a representation requesting them to waive of the last 3 days, however the same was not allowed. 

The other option is you give them a 57 days notice period and resign. Thereafter, once you have joined the company, you can send them a legal notice to give you your relieving letter and your full and final payment within 15 days and if the same is not granted, you can initiate a recovery suit against the company.

But we should warn you that this method will be time consuming.