My daughter won't ever listen to me...

My daughter's 15, a freshman in HS. She never listens to anything I say, despite being so lenient. Practically anything she asks for I will eventually get for her, even though I don't want to -- she manipulates me to the point of doing so (for example, she refused to go to school until I bought her an iPhone, and did it again with a laptop and refused to wear glasses until I bought her contacts)And that's not the biggest problem. The biggest problem is that she never listens to what I say. She purposely ignores it (like when I tell her to get home early for something, or when I tell her to study for a test because she's failing, but she just tells me "I don't care")What really annoyed me was today, when our whole family went out to eat with grandma. She refused to eat with grandma. So disrespectful!Small things just tick her off, like when I ask her to hurry up because we're running late. Just that one sentence will aggravate her to the point she won't listen to you.What can I do? via /r/Parenting http://ift.tt/2iRB126