Your daughter is having an understandable reaction to a difficult situation. Her father apparently lets her down over and over, and she feels sad and angry about this, which she should. And, since you are the folks around her, you inherit the reaction, even though it doesn't stem from you. Now, she is entitled to whatever emotional reaction she has, but she is not at the same time entitled to act out those feelings in ways that hurt others in the family. Continue, then, to set firm limits on the behavior, at the same time as you show understanding about her reactions. As a disciplinary tool, I'd suggest you employ time out more often as a general response to episodes of misbehavior. You can also establish an incentive system, whereby she is rewarded for displaying appropriate behavior,, particularly in the wake of a letdon by her father. Finally, consider arranging some therapy for her so that she can have a forum where she can address this matter with a person who is not in the family and who is trained to help chuildren master such happenings in their lives.