@Inna22 Mischievous kids will take a note on the door as a challenge. When you give guests their introductory tour, I recommend pointing out the door between units and explaining to any parents with kids that this is the spot in the house most sensitive to disturbances. In the long run, it might be helpful to make it look less like a door - perhaps put a heavy sculpture or potted plant in front of it, or some kind of decorative wall covering.
I think the guests who reviewed you left fair and reasonable feedback. There's a huge difference between being awoken to the little brats loudly and directly banging on an unopenable door and the ambient noises of the city, and it's understandable that the confrontational nature of this encounter fully spoiled the sense of privacy your guests sought in an "Entire Home" listing.