Unfortunately, she couldn't comply.
We really wanted to help her out but we're not parents and we didn't have any warm-up to handle a 15 yo from an abusive home.
We were asking a 15 yo to act like an adult. She actually did better than some of the chronological adults that have stayed with us. But then, she was staying with us for significantly longer.
Also unfortunately we were still rather fragile from all the other events that have happened this year.
What this means is that while one of the reasons that we have a big house is to guest people, right now we can't do so. I don't know when we can but we have to stabilize ourselves before we can offer an environment to others.
P.S. "Our" teenager is now with a friend of hers whose mom has told her that she will be treated the same as her own daughters.