Teen daughter is manipulative

My 13 yr old,teen daughter returns from school and takes her mobile phone. She talks with friends for hours together. She doesn't study at all. She keeps talking to a particular guy late at nights. She's not amenable to any middle ground arrangements. Even if she agrees, she breaks the arrangement in 2-3 days by threatening to self-harm or walk out. I have no idea what to do and I am walking on egg shells. She is completely out of instructional control and screams if I try to preteach.