My family was staying in a pagdi flat which was in the name of my father's elder brother. Both brothers had mutually agreed that the rights of this flat to be given to my father(younger brother). My family has all documents like aadhar-pan-voter id-passport at the same address. The building is now under redevelopment and the totally mannerless builder is making agreement on my father's name by demanding 10 lac cash-No rent for all the redevelopment duration-No extra fungible space & that i should pay 6% stamp duty also... We are very depressed and helpless.. Please suggest what to do..