Pagdi System Redevelopment - Landlord Asking Letter For Closed Flat

We are having a closed flat since many years in a Pagdi system building and are residing elsewhere. The landlord is not accepting rent from anyone in the building since 2015. Now the landlord plans to go for redevelopment himself soon and has now started clearing the due rentals for all flats in his building. For my flat which has been closed since some years, he is demanding a written letter stating the reason for it being closed. He is not ready to talk on this or accept any pending rent from me without a written letter from me. However, the ask for written letter is verbal and not legally. For some other closed flats who have already given him a written letter, he seems to be asking for a Penalty amount for keeping it closed i.e. 20,000 x 5 years (2015 - 2020) = Rs. 1 lakh. Post this he is accepting rent of those tenants. I asked him if I would give a written letter, pay up the rent and penalty he asks for, can he confirm in writing that he would not go legally against me for eviction after this. - He said he cannot give me anything in writing for this. My queries - In this case should I give him a written letter confessing my flat was closed or should I not give him in writing and wait for him to take the next step. If I give him the letter, pay penalty and rent, can the landlord still possibly go legally against me and send me an eviction notice. Is it advisable to give him to the confession letter from my end. If yes, what reason should be stated for keeping it Closed. If I do not give him the letter and he refuses to accept rent, what could be his next steps and what should I be prepared for. Is it legally advisable to give in to his demands of a written letter and Penalty amount. I am in two minds and unable to decide. I need to respond to him in next 4 days. Please advise.