Harrasment to senior citizens by Neighbour.

Hello, My mother is 69 year old widow living in a building flat no 704, and our neighbouring aunty who is a widow as well, same age as my mother living in flat no. 703 Are harassed by flat no. 701 My mother and aunty are residing in the society since 2001 And flat no. 701 have shifted 3 years back. He is a managing committee member, family of four wife and 2 sons. Since they have come they have created nuisance. They do not follow any of the society rules. As per society dustbin should not be kept outside the house at night, but they kept it out at night and cats used to drop the dustbin and made the lobby dirty and making my mother's entrance dirty. My mother used to tell them nicely but they never paid a heed. 2 Months back my mother made a complain to the managing committee, since then they have started harrassing more. Recently they have installed a cctc camera on their door, without taking permission from the neighbours. My mother and flat no. 703 aunty made a complain to the managing committee to ask them to install the camera inside their house because the camera is violating our privacy. Now their harrassment has increased. As the flat 703 aunty lives alone and has no kids. Flat no. 701 Husband wife are torturing her by saying, that you do have kids, you will die alone, your body will rot and decompose and nobody will come to see you. And also told my mother and aunty that I will see how you both live in this society. My neighboring aunty is very disturbed and she is crying since then and my mother's mental state is also not good. What if anything happens to anybody. Society managing committe has told that we are noy in this matter anymore. Now We want to take action. However we need proper guidance. Please help.