I have a teenage daughter who is making really poor decisions, I was able to keep track of her location until she learned to turn off her phone while she doesn't want to be found. Has iPhone developed an app to install a passcode lock to prevent the phone from being turned off?
Although you've probably seen this page, here are the restrictions you can enable on your daughter's iPhone. That's it.
Although I'm in no position to know exactly what is happening here, I can tell you that technology is not the answer.