I need help getting into a parent account.

My mom made a parent account and added me into her family, she forgot her live email so she can't even access it. I can't download apps or anything because it says my parent needs to accept the terms and services thing but she doesn't even remember her log in. How can we find the back up email she used so we can send the account recovery information there? I really need help otherwise my phone is useless. If someone knows how we can do this please reply! I'd greatly appreciate it.