Teens can be tricky anyways. Try to assume some of it is normal teen behaviour, like the obsession with the phone.
Look for the "moments" they seem open to talking, etc., try to be ultra aware of how you respond, be more curious than opinionated
Try to let them talk, draw them out (very carefully as not to alert them to your intent
)
I'm being funny, but I have raised five teens and it's a tightrope at times. It will pass. Stay interested in what's up with them and "fascinated" by their thoughts, even when they are wacky. Thoughts aren't forever with teens, I just let them tell me for example how much they want that tattoo, but as of yet, none of them have one. ( not against tattoos, just the random example). If I had said "NO!, I'll never agree to a tattoo" I would have shut them down.
But instead say, oh really, what would you get? Do any of your friends want one? What would they get? ... .and now I learn about them, their friends, and they feel I'm listening and get them.
Hope this helps, good luck.