Don't have password, can't sign out of Find My iPhone, and have Assistive Touch for Sleep Button. Help?!

My mother took away my phone and changed the passcode. Now she forgot it. She's been laughing and playing around about it, but I'm majorly ******. I didn't do anything to have it taken away. She took it away solely for me calling her at school to pick me up because I was sick. Now it's disabled and I need it back, because I'm going on a trip and I really need it. My sleep button doesn't work, and since I can't go into my phone, I can't turn off Find My iPhone, so I can't restore it. PLEASE HELP I NEED MY PHONE. Just- please. How can I restore it, or turn off iCloud? I know there's iCloud.com but it didn't work and I erased my phone from it so it's seriously not working. God this is horrible.