suggestion

what to do when your 14-year old czn misbehave with you because you confront him bcz you saw him changing your mobile setting ..and he shouts at you and says what can you do if i did it...when you tell him its his mistake but still he says what can you do..he is bigger then me in hight. i was shocked to the core but still it was not the first time he did something..also cant tell his parents bcz they are same and thinks their child is on right track ..and your father is not here and mom just wat you to shut up to end the fight  /////please i really want a suggestion on this