Prove that you are trustworthy, or agree for them to put parental controls on your phone. You can do this by letting them check your phone whenever they want, and keeping your search history up so they can check that too. Over time, they will be confident that you are not doing anything you are not supposed to.
When you call a dead phone does it ring?
Answer: A: With a dead battery it should not ring but it should go to voicemail directly.