Sometimes teenager's behave this way due to their friend's, with whom they are hanging out with, or how much freedom their own parents allow them to have or what or who they are communicating with on the computer. If they so much believe they are adult's, I would also strip them from all their video gaming's and their console's, remove their computer out of their room and their tablets, Do not allow them to use your computer if you have one of your own, even if they insist, they have homework to be done in the computer. They're teacher should comply and understand, they are grounded and the computer is off their limits no matter what. Have them pay rent, have them pay part of their usage of the electricity and water bill's. Have them and help them get a part time job, a job that contributes to working right after school, and on the weekends as well, after work, off to their room they go and do their homework. Do not pay for their cell phone service's even if this mean their cell phone will be shut off. Their friends are not allowed to come over to the house. Upon purchasing the groceries, have them pay part of the groceries. If they are still in school, make it your business to pick them up and drop them off to school yourself. When they come home from school, have them remain in their room till you say it's okay to come out of their room, set a sleep time hour. It may be hard for you to gasp at first, but you have to put that aside and think to your self, better have a child who is well behaved and respectful then a having a rebellious child within the family, who might be hitting the streets, hanging around with the wrong crowd and dealing with drugs. Before you know it, your own kids will physically beat you down. I seen all this happen to 2 of my siblings and their kids. Best of luck to you and I wouldn't wish this not even to my worst enemy. If non of this helps, I suggest you to send them to a boot camp. It's totally up to you.