How To Manage Significantly Negative Behavior Of Stepdaughter?

my husband was with his ex wife for 8 years and helped raise 2 of her children. one which was raised to believe he was his father. the older is an 11 year old girl who was a year old when they got together. we had many issues with the girl as soon as me and my husband started dating. she would tell me personal things and when I gave her advice she would tell her mother and cause arguments, if she didn t get her way she would call her mom and say myself or my husband was being mean to her. the latest incident caused us to stop getting her all together. her and her mother had seen one of my husbands family members at a local store and said that I had told the child that she wasn t my husbands responsibility and that shes not coming back to my house. I had never said any of that. I have done everything in my power to please this child to get her to like me but I had to draw the line. my husbands family doesn t agree with our choice not to get her anymore. they say she is just a child. but I feel she is old enough to know right from wrong. what is your opinion?