My step daughter came to live with us two months ago. she does not want to abide by our rules .?

Give it some time, she will come around. She probably feels a little unwanted, and feels like shes getting tossed around like a rag doll. She originally lived with her mom and probably feels a little bitterness towards her father for "leaving" her. Try spending time with her, get to know her. She will come around, I did. :)