Lil siblings trouble..?

I cant take it any more. My 6yr old twin lil bros r driving me nuts! One kept me up all night the other is a MEGA brat. If he doesnt get what he wants he throws everything on the floor n goes to my dad n tells him i did it. They snitch me out. They throw sheet at me n kick me! They go to the neighbors house n NEVER come back on time. If they dont get what they want they throw a tantrum hit u throw stuff at you. They act like angels when my parents are home. When i have to babysit them when my parents aren't home they go DEVIL! They dont even listen to me. I tried being nice im done with it. It doesnt work. How do i make them listen to me n to make them stop being brats