cannot log my kids in and mobile app keeps crashing

Hey it seems like you are already working on it, but man I've had a heck of an afternoon trying to get my daughter's minecraft to work.  I had to reset her phone and re-install everything today, when I went to login to the minecraft app it said it was trying to login with her Microsoft account.  But since I didn't install from a back up there should be no record of her logins.  I can't find ANYWHERE to specify her credentials.  It keeps just endlessly trying to login.  When I cancel it tells me it has had "a problem".  I see the pop up for the bug fix now, but at this point, the app just crashes every time I click on that thing.  Keep trying. Order some pizzas, have some more Bang, do what you do, but PLEASE solve this problem soon???