iPhone iOS 7; wrong Apple ID
I just updated my iPhone 4S to iOS 7. Find my iPhone was set up using an old Apple ID (one that I don't have the password to anymore). I cannot log out of iCloud, turn of Find my iPhone or use the correct Apple ID. Does anyone know how to fix this problem since I do not have my old Apple ID password? Also, does anyone know why -when updating to iOS 7- my phone reverted to an old Apple ID?
Thanks!
iPhone 4S, iOS 7