I am in desperate need of help with stepsons!!!!?

Ok so here is whats going on. My 2 stepsons (11 and 13) live with us. They have lived with us for about 5 years, and were doing great in school and just good kids in general. Now they have done a complete turnaround. When they were in school, they both got almost Straight F's, they have no respect for anything or anybody. I tell them to do something and they just ignore my husband and I. We used to make them stand in the corner with their hands up, because my husband was not allowed to them because they were abused by their egg donor. And then the judge told us that we couldn't put them in the corner like that either. No punishment works with them, we have tried everything from groundation to taking everything away and nothing works! I think some of it is because when they go to their egg donors house she doesn't follow through with them being in trouble. I am just so stressed out with them. I want to just give up on them, but I just cannot find it in my heart to do so. Someone please help!