I read this book a few years ago. (Between 3-10) It is about a woman who keeps getting mistaken for a popular super hero and attacked by villains as she works at a fast food place. Nobody believes her when she tells them that she isn't the hero so she has to defend herself. She uses a fire extinguisher to defeat one villain. The villains do have powers but the main character does not.
There's a cop that keeps trying to get her to admit she's the super hero.
Her friend visits the fast food place and I think draws. Her friend is secretly a super hero. There's multiple mentions of insurance covering things.
I believe the superhero may turn out to be her twin sister in the end. It's a series that I found on goodreads. Very light and short books. Possibly novellas.