Downgrading to a dumbphone

Not trying to give you parenting advice or anything but from my experience (as a 16 year old kid) I got a lot of bad grades and my parents have tried most everything including taking away my phone, giving me a bad phone, taking my computer, not letting me go outside and some of it worked, but phone just did not work. One thing they did which I look back and though it was real funny yet worked was they took every item out of my room except my desk and matress and dresser. Let me tell you it really sucks to have no computer / tv / items you can use / play with in your bedroom. Also grounded me and a week later my grades were up... but of course didn't last long. If they were to take my phone or give me a junk one I just wouldn't carry it around. I'm doubting he will let it affect him if he is "smart" persay in avoiding your punishment tactics he will just find a way around it such as an ipod or friends phone or get old games on his old phone haha flip phones even have games! Talk to him about his future and what he plans on doing when he can't graduate highschool and get into college. Thats what my parents tried to do until I told them I didn't plan on going to college for a degree. Worth a try? If not you can get parental devices for smartphones where you can block them from getting on internet and playing games at certain times I know sprint offers a lot of that.