Illegal construction at Debottar Property

For 50 years we are tenants of a house which is a Debottor Property. There is a Trustee Board who leased this property to a person who rented this house to us. My father was the original tenant and after his and my mother's demise I became tenant. The house was in dilapidated condition and I came to know original owner kept Municipality property tax due for several years and Municipality was pressuring me to give the money or they will cut off water supply. I gave letter to my landlord and stopped rent. Later I handed over house keys to landlord to repair the house and took receipt from the person who came on his behalf to collect keys mentioning in receipt why I am handing over keys. My service took me to a different city. After a year when I came back I came to know from my landlord's son that original owner's one of the legal heir has come to agreement with a developer , keeping all other heirs in dark, by deletion all records of Debottor status and hushing up the trust deed, and right now construction is going on for flat building. Now my landlord's son ( my landlord died a year ago ) tells me that they were tenants and not leaseholder so subletting it to my father was illegal act done by his father. I want compensation or share in construction as old tenant who duely gave rent for more than 45 years with receipt. What should I do ?