The 4th Floor (1999)

A young woman moves into a new apartment that she inherited from her grandmother, who had died there in a bizarre accident. She is immediately confronted by totally bizarre neighbors and someone is obviously out to get her as rats and flies engulf her apartment. But with the array of weirdos around her, who might it be? Everyone warns her to stay away from her upstairs neighbor, but he is the only one who shows any kindness. Supposedly the neighbor below her is an 80-year-old woman, but she hammers the floor so hard when the young woman moves furniture that she breaks tiles. Another neighbor seems kind enough to begin with, but later seems more interfering and threatening. Also her weatherman boyfriend can't be ruled out. Contrary to his desire for her to move in with him, she moved into their apartment.