Sounds like you and your DH need to work on them being obedient. Once that is resolved them will be obedient in every area not just school. Since they are already teens it will be more difficult but well worth the effort. My DH and I have raised 15 (all home educated) children and I am down to my last one now.
well I am almost done with my last one in homeschool and teens can be hard. 1. you need rules. 2. you need to stick to them and change 3. have a goal at the end of the day if they do school. My youngest was very antsy all over the place. We had to set goals to get through the day. One if you want to do this in co-op this has to be done at home first. two life isn't easy and bed of roses sometimes we have to do things follow rules rather we like them or not. Video games were not allowed if school work wasnt done. School comes first in our house.