Smartlock kills any music app. Will throwing phone fix it?

Phone was fine for a few hours after I bought it then a notification asked me to o confirm something to do with hand detection & phone being always on when it detects your hands now I can't switch it off, music stops after screen lock and screen on leads to inadvertent clicking even when putting in and out of pocket. Update is so frustrating! Tried everything to change it; all online threads report similar failure.