The 4th Floor (1999) on Netflix

Plot summary

The apartment comes to Jane Emelin from her late aunt, and she decides to live there alone for the first time, despite the appeals of her boyfriend, Greg Harrison. Martha Stewart, who lives on the first floor, lists the other occupants of the building for her, among them a recluse named Alice. The next morning a note is on Jane's door, objecting to the noise of her moving in; a second note follows, and someone has meddled with her locks, so she calls a locksmith. The neighbor below her hammers until the kitchen tiles break, and Jane answers with noise of her own and a call to the police. She befriends Albert Collins, an old man who knew Greg in high school.