It's great you can enter your phone number to determine if your mobile number was part of the Facebook break, but WTF is international format. A Google search is no help. For Americans, is it with a "+" at the beginning, or just a "1", or is it a "+1" followed by area code and number? I'd like to know I'm entering my number in the format you need so I can be confident that your "no" answer can be trusted and isn't providing a false negative. Just provide context sensitive guidance.