I'm pretty sure it involved either 2 sisters, or a mother and a daughter, or maybe just 2 close girl friends, being terrorised by one of their ex-boyfriends, who eventually gets into their house to attack them. I think they manage to trap him in the basement or possibly the attic, and there is a lot of emphasis on them not letting him escape the house once they've trapped him.
any ideas on that vague memory, I know it's not much...