We have made considerable efforts to place appropriate controls on his phone, but he circumvents them in numerous ways.
When that has happened, we have taken his phone away, but he somehow gets a hold of burners or borrows phones from friends. This issue has caused so much damage to our relationship with him. The struggle back and forth has led him to be incredibly dishonest with us.

We have continued to fight this battle with him because we know how damaging unfettered smartphone access can be to teens. Although our intentions have been good, he doesn't accept them and only sees our attempts to place reasonable limits on smartphone use as controlling behavior. We are at our wits end about this. It now feels like it would have been better to just allow him access and then deal with whatever problems ensued. At least then, we could possibly enjoy a relationship of trust with him. But this struggle has pretty much destroyed all trust and it is incredibly difficult to re-build.