Step daughter hates me

I have been a wonderful relationship for just over 2 years. things are going swimmingly EXCEPT his 9 year old daughter does not like me. She tolerates me pretty well. but anytime I tell her no she screams she hates me and hits and bites and was the other day screaming in the middle of the street with one shoe on curled up cause her hair isn’t long enough to put in a pony tail.. shes the one who got the haircut .. she chose the length.. her bahaivor is better when her father is around. but she will always scream your not my mom .. life was better before you ect. She has no realtionship with her “real” mom. she hasn’t seen her in over 1 1/2 years we still have her christmas preasents wrapped.. her mom will not call us but when she was at her grandmothers her mom did call 2 times. (sub question) should we even allow her to talk to her mom anymore? we are always if not friendly than civil, she is not allowed to take her off teh property but there visits are as unsupervised as they can be in our home.. I just want her to understand that I want the same for her as my own 2 kids - 1 full time like her, and a daughter her age on the weekends - the rules are the same but my stepdaughter gets less freedoms because of her behavior-ADD by the way on top of it all. I just want to help her I want her to accept me and let her know I want the same for her as I do my own to kids.. just for honesty sake I dont care for her as much as I do my own kids .. do I pretend aka fake it till I make it … it has coused a lot of stress in my otherwise blissful relationship