Yes... do all you can... and they find a way to do it from someone else.. somehow, they want to show they can do whateer they want to.. and taking it all makes them more determined.. but take it all.. ya have to do that..
She is 15. She is a minor. A minor cannot sign a contract to purchase a cell phone. If somebody sells her one sue them. Actually it should be illegal to sign-up for a social media account before you’re 18, though as a practical matter I don’t know how you’d enforce that.