We are living from more than 50 year

Dear sir/ma'am, We are living from more than 50 years & above in Mumbai Suburban city .Due to 1975 law we paid rent to Government and the government stop the rent as it was pagdi system .Our room is not in condition to stay as we want to renovate the room and we had approached to our landlord for this he claim.that you are renter had you have to pay rent in this year in pandemic he had send us a letter from advocate which and illegal paper a common paper with no register number that the lawyer had mentioned that from 1973 to 2021 you had not paid the rent and you illegally live at his place he can take any action and can take you out of room we had our own light bill, water bills and more on my grandfather name for more than 50 year our grand father name .Now we have to make our home for renovation because now the room is wall are broken but the landlords is not approving to renovate it he told we had talk and we had cased to lawyer read 2015 new law and all we will not give you the permission and pay the rent .if we asked for ownership he told us no we won't give you and all .So what so we do ? Now please help us