Resignation from service - not released even after about 4 months

I have been working with a PSU. I resigned about 4 months back citing personal reasons and better career prospect. As per the company procedure I agreed to serve three months notice. The divisional head during the exit interview (happened very late, after two months) advised me to accept a transfer to another division instead of leaving the company, which I politely turned down. However, he wished to go ahead with the decision to transfer. Subsequently I discussed with my boss and the HR head repeatedly about my unwillingness to transfer. Still a file for transfer was initiated. When I heard about it, immediately I wrote a letter to HR through my boss stating my unwillingness. What followed is simply frustrating. The entire thing became very secretive and I have been denied the real information about the file. Even till the last notice day I could not get any useful information. It compelled me to stop reporting to duty (after 3 months notice), which I did after informing the HR in writing through internal mail (I intended to submit a signed letter but my boss disagreed to sign it). Subsequently, after talking to other concerned departments and expressing my unwillingness, I was told that the file would be processed for resignation. However, even now I do not see any real progress. In this situation my questions are: 1. What is the possible legal action that I can take? However, without any disrespect, I am apprehensive about the possible delay in court (I need to join a job after getting relieved from here). 2. Is it possible to claim releasing letter and experience certificate from the company by filing an RTI application?