Encroachment of my land

Sir my father was purchased one Katha land more than 15-20 years ago. A few years ago we want to construct a house on that land we come to know that there is no way to go in my land which was purchased by my father. So we approached to land owner and they intimate that this is not your land as per measurement. After repeated requests they direct my father to measure your land by hiring Amin. Thereafter, we hire an Amin who measure the whole land and intimate that there is a approx 12 feet way to reach my land which was boundrywalled by brother of land owner. On requesting him to break his boundrywall, they denied that they are not agree for this measurement and direct us to carry out the whole land measurement through official. Further, my father submit an application in block for said purpose and the measurement also come in our favour but he couldn't break his boundrywall. In this regard, my father approach in near police station to Lodge a complaint but they couldn't Lodge a complaint and intimated that there is no role of police and advised my father to file a court case. Sir please guide me what I do and how much time taken if we file a court case.