Ouch is right. Adolescent girls can be tough! And I can imagine that it's even harder when you and her dad are not on the same page.
I don't have any great advice...except to remember that you can only control YOU. As someone who has worked with 11 year olds for a long time, I can say that they sometimes have trouble seeing beyond black and white.. but also often respond well to positive attention... letting them feel like they have some control... and definitely modeling (and explicit coaching) on appropriate behavior. In other words, remember what you tried when she was 3? It's kind of the same thing now. (!!)
If I were you, I would probably try to avoid situations where she will be in the middle of a power struggle between you and H. (Taking things away doesn't work that well, anyway, TBH, and it certainly won't work if her father just gives in. In fact, that will be WORSE for both of you.) If you feel like you have to take something away from her, it should be something that you have control over without having to rely on H to back you up. (not easy, I know). That will help her respect you more, I think.
Have you read, "How to talk so kids will listen..and listen so kids will talk"? Sometimes "ugly" behavior is really a call for help. If you become the person who truly listens to her, even when she is acting "ugly", that will help your relationship in the long run. Model for her what effective conflict resolution can look like, especially if she didn't see it in your M. If you don't know yourself, this is something you probably want to discuss in IC or to read about.
Hang in there. And keep at it-- she is at a pretty critical point, right on the edge of adolescence and going through a parents' divorce. YOU can be a really awesome guide and source of strength for her!
