Harrasment from elderly couple and their minor son

Hello, I'm a 24 year old lady residing in an apartment where most of the people are above 50 years. We reside in 3rd floor and opposite to us lives this extremely old couple who are above 70years most probably and with them reside their daughter who is also quite aged, she had an affair with a married man long time back and had a son which the family refused to accept. She resides with her parents opposite to us. Now we buy things most of the time from online platforms such as amazon flipkart and myntra and all the delivery services are done by men. So they started nitpicking on us saying that I'm doing some kind of prostitution business here as men often come to us and the elderly women along with her daughter and son started hurling me with abuses every time we came face to face. After few times the elderly women started throwing her trashes in front of our gate and also started writing abuses in our side of wall. When we complained to the flat association about them they fought with us and all of them saying that they will beat me up if they see me out of if anymore men came to our house. After all that they haven't done anything yet but still at times try to get into our business and start fight. I have made a police complaint and have kept a copy of it with me but them being old people does not have much to tell them. And the elderly women takes profit of this situation and she initiates the fight all the time. I want to know if there are any legal provisions by which I can somehow keep them in checks so that they don't have the courage to disturb again.