My brother has constructed cement wall and done partition of the house

I live on ground floor and we have a 3bhk flat in a co-op society. The flat belonged to my grand mother and later transferred on my fathers name. My brothers name was added as a nominee so society has transferred it on his name on the share certificate after demise (2015) of my father. There is no will made by my grand mother or father. 3 yrs back my brother built a cement concrete wall dividing the house into two parts. One part consists of 2 bhk and other single room. He has forced me to live in one room and remaining 2 bhk is given on rent to third party. I have filed a suite for joint ownership and registered a complaint in BMC but no action is been taken by BMC so far. I had called police also, but they said it is a civil matter and only court or BMC can take a call. What can I do in this case to get the wall demolished at the earliest so that I can get full access of the house?