OMG do you live in my old building?
This happened to me, over my bedroom/bathroom. We had a 2 BR/2 BA, and the neighbors upstairs somehow overflowed their toilet...well, the guy was home all day, (playing video games, I think), and never noticed!!! 9 hours of running water made for quite a scene when I came into my bedroom after a long day-I flipped on the light switch, and it was POURING through the light fixture, dripping from the ceiling, and running out of the vents!!! I immediately called after hours maintenance, and they went up there and disconnected it, and then brought in big fans to dry it out right away. BUT, they wouldn't pay for a hotel or anything-but my room was soaked!!! I couldn't stay in there, and we weren't supposed to use the electricity since the water was also running out the outlets in the adjacent kitchen wall!!! We went and stayed at a friend's, and then after a day or two, it was mostly dried out.
Oh yea, there were no consequences for these people, and they too used to put dog poop in bags on their deck, and somehow the "wind" would blow the bags down onto our deck
I feel for you!
My best advice is to report these people to the management for EVERY little thing...I know, we all hate to be "that" person, but in cases of extreme neighbors, it's best to document each incident!