Revoking notarized NOC

My Grandmother and grandfather lived in mumbai pagdi chawl with 5 kids. Both of them had one room on their name each. So 2 rooms (one bigger and one smaller on each of their name on rent receipt) my grandfather died in 1994 and grandmother died in 2004. By Then all of their kids got married and moved out except their eldest son who continued to live in the two rooms with his family. In 2004 he got the rent receipt of the bigger room in his name without informing any of his siblings. The smaller room rent receipt still bearing grandfather name. Now The Building outs ready to go into redevelopment and a builder is now the new landlord. Out of 5 siblings, the eldest daugter is expired now and I am her daughter ( i have two more siblings) the builder advised my uncle to get NOC from the remaining 3 surviving siblings to transfer the smaller room on his sons name who stays with him. So he can keep both the rooms to himself. The 3 siings objected and that's when I found out that they need me n my siblings NOC too as we are heirs as my mother has expired. The uncle presurred us into giving NOC to the bigger room and he gave his NOC to smaller room ( his idea that he keeps bigger room to himself while the smaller one can be divided among the rest of the heirs..otherwise he will get the rent receipt transferred on his sons name by having some set up with the builder landlord). Mhada is building authority so they too asked for a family settlement. So we got one mou and 2 NOCs which did as per my uncles wish. Mou and NOCs are notarized and submitted to landlord and mhada. Now I still feel cheated and think that both the rooms should be divided eqally among all the heirs. Is there anything that can be done now ? Can we revoke the NOC and take objection now ? I want to know my possibilities..pls help. Thanks a lot.

My Grandmother and grandfather lived in mumbai pagdi chawl with 5 kids. Both of them had one room on their name each. So 2 rooms (one bigger and one smaller on each of their name on rent receipt) my grandfather died in 1994 and grandmother died in 2004. By Then all of their kids got married and moved out except their eldest son who continued to live in the two rooms with his family. In 2004 he got the rent receipt of the bigger room in his name without informing any of his siblings. The smaller room rent receipt still bearing grandfather name. Now The Building outs ready to go into redevelopment and a builder is now the new landlord. Out of 5 siblings, the eldest daugter is expired now and I am her daughter ( i have two more siblings) the builder advised my uncle to get NOC from the remaining 3 surviving siblings to transfer the smaller room on his sons name who stays with him. So he can keep both the rooms to himself. The 3 siings objected and that's when I found out that they need me n my siblings NOC too as we are heirs as my mother has expired. The uncle presurred us into giving NOC to the bigger room and he gave his NOC to smaller room ( his idea that he keeps bigger room to himself while the smaller one can be divided among the rest of the heirs..otherwise he will get the rent receipt transferred on his sons name by having some set up with the builder landlord). Mhada is building authority so they too asked for a family settlement. So we got one mou and 2 NOCs which did as per my uncles wish. Mou and NOCs are notarized and submitted to landlord and mhada. Now I still feel cheated and think that both the rooms should be divided eqally among all the heirs. Is there anything that can be done now ? Can we revoke the NOC and take objection now ? I want to know my possibilities..pls help. Thanks a lot.