Full and final settlement pending. Resigned 3 months back. What to do?

As you mention that you resigned by 'mutual' communication, there must have been some terms on which you and your company decided to part ways. Did those terms include the time in which the company was to release your Full & Final payment along with other dues? Was this communication verbal or through email / documented?

Answers to these questions will enable us to provide you with better assistance and suggest proper legal recourse.

The course of recovery of your employment dues depends on the nature of job you were rendering. If it was clerical in nature, the Industrial Disputes Act would be applicable and you can get the desired relief in the labour court. 

You can file your complaint for financial dues including salary and other applicable benefits. For PF withdrawal, you have to move the prescribed application before the concerned PF office authorities and in case of no action by them, you may write in to the PF commissioner stating your woes and inaction by the concerned authorities.

On the other hand, if your job was of a supervisory nature, you have to give a Legal Notice to the management for payment of financial dues, which include salary arrears, gratuity (if applicable), leave encashment etc.

If the management does not respond positively or does not pay in the stipulated time of 15 days, you may file a Civil suit for recovery of financial dues in the relevant Civil court by paying the relevant court fee. Any documentary evidence like communication at the time of resignation will be beneficial and support your cause / case.