Y'ALL I'M SCARED ASF RN

So someone keeps knocking on my fucking walls from outside and looking through my window at me. My parents are frequently out of the house and I'm not really capable of self defense. I've called the cops 3 times now but they've found nothing and said if I call 1 more time pranking them they'd have me arrested or they wouldn't come. Now I'm scared that one day they'll come into my house and do something horrible...