Hygiene & bad attitude from the owner/ manager

As my sisters lunch was delivered she saw a hair strand in it. We called our waiter who sincerely apologized for what had happened. We then requested to see the manager. All I received from her was her ****y and ****** comments gloating about the establishment she runs and insisted that the hair did not come from her staff as if my sister put the hair in to avoid paying the bill. All I expected from her was an apology. It's unfortunate that this was one of my favorite restaurants which I'm no longer going to support.