Query regarding law for cctv cameras

I live in residential building (back side) in which there are 9 flat front side & back side my neighbour who live in my front side installed cctv cameras in front of my main door stair (common area) without my consent & it monitors both flats stairs but I don't want this cameras coz it monitors my movements & she turn off cameras as her wish she first assault me & then start the cameras when I do my defence I made many police complaints but police says she has consent of other building members