Mental harassment by neighbour

Hi, thanks for your time. The secretary of my building has been mentally torturing me and my family for about 4 years now. She is the sort of person who is terribly inquisitive about other people's business and very nosy. Her favourite pastime is standing at her window, supervising every activity happening in the building. Who comes in, who goes out, who comes with whom, who wore what! Not only does she gossip about all of this to anyone and everyone, she also does her fair share of moral policing based on this and harasses everyone. She can't stand the thought of other people being happy or enjoying. She has given the watchman instructions to lock the gate by 11pm. After that no outsiders are allowed into the building! Its worse than a college hostel. Also, the terrace has been locked under her instruction lest anyone commit suicide :|. She's uneducated and extremely unpleasant to talk to. Its impossible to talk logic to her. Just because of her personal vendetta against us, she has charged plenty of fines on us and interest on those fines is accruing to a huge sum. She passes comments whenever we walk past. She spreads false ideas about my father just to turn everyone against him. She is always ready to spit and bark at the drop of a hat but being educated, decent, well mannered people, my family finds it tough to put up a fight with her. It is a very hostile environment to come home to after a tiring day at work. Her jealousy is endless and she just can't learn to mind her own business. How do I make sure she learns her lesson?