Neighbor hit our child and denied

Our neighbor hit our child when he was only 3 in school bus in our absence and denied it. They even abused us when we complained to school(school diary). their daughters started harassing our child in school/school bus)pinching/pushing while getting down from bus)when no one was watching. We had no evidence because we could not travel in bus with child. we changed our childs school. Now around 1 year back her daughters spitted water outside our house intentionally. when we complained in the apartment office they installed cctv to spy on us. they have locked our main door 2/3 times and because of this our main door is open sometimes because we are scared. Now they are threatening us that they will file a FIR/criminal case against us because we are teasing their daughters inside our house. We never use the same lift which they use and this lady goes and complains that we are stalking her which is not true. She works as a teacher and we are scared that she may join our childs school and harass him. she goes to the police station with the cctv footage inside our house and complains that we are teasing her. She gossips in the apartment and outside about us by showing cctv footage and makes fun of us.