Get rid of the phones in your house except one in your room that you can monitor. Take the remaining phones and put them somewhere out of her reach, maybe a friend's house. Tell that that she can earn her phone privileges and privacy back SLOWLY (maybe 15 minutes per weekday and 30 per weekend) if the next phone bill is reasonable and another 15 minutes if the next phone bill is reasonable. If you leave somewhere, you can always take the phone with you. Another, maybe easier idea is just to get a cell phone. You could probably get a family plan and restrict her minutes.

The back-talk is a harder issue. You have to be firm and show her that you're not %#@&#! around and demand respect. If you don't get that respect, start withdrawing privileges that she has. Keep in mind that the process is going to be easier if you treat her with respect rather than as a subordinate.