Arig, i feel for you and what you fell for!
Now that she is there, you have to try to work things out and teach your daughter some real life lessons.
Perhaps you speak to the mechanechet and help set your daughter up with a family where she will feel comfortable and the mother/father can be her mentor and hold her hand while you are not close to her.
In Mir, the bochurim are today hooked up with such. I know, as my son is the shoulder for some bochurim. They feel close enough to discuss their doubts for whatever it is and have a place for a good home cooked meal and some real family life, not yeshiva/seminary lunchroom dynamics that sometimes does not see a mechanech/mechaneches and the kids are busy with such as bottomless texting and that starts their sliding down from Torah life!
Hatzlochah!
If your daughter is adamant of coming home, tell her that the condition is to get a job and pay back the $21,000!!!!
Gut Shabbos, Good Luck and a Gut Gebencht Yuhr.