What can I do if my neighbor has damaged my property?

I purchased a flat on top floor (4th Floor) with some extra space in the front of my flat. For my convenience the builder has made the plaster and applied titles on the extra space. My Neighbor Harish Rawat R/0 C 608 A 3rd floor JVTS Garden is not letting me use that extra space saying that he has roof right. He has also built a tall wall in front of my house. The construction was done without any permission/NOC from MCD. The construction was done at a time when the construction was banned in Delhi due to pollution. During the construction he has also broken two lines of tiles and occupied some part of the extra space. I made a complaint in police station and MCD but by the power of money my neighbor Harish Rawat has suppressed my case. What should I do.