My grandmother was staying in a flat which she bought. She gifted the flat to my father. My father a

My grandmother was staying in a flat which she bought. She gifted the flat to my father. My father and mother were divorced and now my father passed away. I am his only child and I was going to the flat on and off but we were not in good terms with my father's brothers. Muy father registered the gift deed but did not transfer in the society. Now his brothers have taken my grandmother to their place and put a lock on the door. My grandmother's favoring them in talks. I wasn't staying there but now I want to so how do I go about it?