It sometimes takes time for things to work their way out. It's not like we decide to do the right thing, and everything lines up nicely for us.
You ARE doing the right thing, and don't stop just because you aren't getting the results you want immediately. I TOTALLY understand your disgust and frustration. Those are valid feelings. But what we have to do is to work past them, because they can keep us stuck if we live there.
This is a roadblock, a pothole, not the end of the road. You will get through it. All I can say is that in many of the cases I handled as a prosecutor, these guys push and push, and the more untouchable they feel the more careless they get and sooner or later it does catch up with them. But it won't happen if you give up.
Take what comfort you can in knowing others have been through the same thing and eventually came out happy and whole on the other side. You can, too.