Devoured (2012) on Netflix

Plot summary

To pay for the operation her ill son needs, Lourdes has left El Salvador and come to New York City, leaving the boy with her mother. She takes a job cleaning an upscale restaurant, where her boss treats her badly, her boss's boyfriend assaults her, and men press her for sexual favors. She cannot risk losing the job, and though she is unwilling to sell herself, she will do whatever it takes to raise the money. Phone calls home to her son and conversations with Frankie, a firefighter who is kind to her, are her only comfort. One night while she cleans, shadowy figures begin to appear to her, and she feels they mean her harm.