2BHK Pagdi property in Kolkata - Property not suitable for living

Hello Sir/Madam, We have bought a 2BHK flat (on 1st floor in a G+2 building) in Kolkata in the year 1997 under Pagdi system. In the year 2013 we had to leave the flat because the condition of the building was getting worse, we tried to contact the landlord for the same but he did not pay any attention. So for the security of my family I had to leave some of my things in the flat and shift to another flat. We kept on following up with the landlord to fix the building condition and come up with a solution so that we can start living in the flat again but we where not able to contact him over call or face to face. We were not sure whether he will be repairing the flat or intentionally wanted us to leave the flat so that he does not have to give anything to us for vacating the flat. After deciding internally and with no option left we requested him to come over a settlement where he can pay us an approx. lump sum amount where we can atleast move out of the flat with our belongings but he did not do anything. So right now the current situation is like we have kept few our belongings in the flat and locked the flat for the last 6 years and visit the flat to check the condition every 3 months and meanwhile the rent of Rs. 900/- which was supposed to be paid to the landlord had to be paid to the goverment under Rent-Control as the landlord is not accepting the payment and in-directly wants to prove that we are the defaulter and vacant the flat without any lump sum amount to be paid.