FaceTime won't verify my main email address and can't use FaceTime over cellular network after downloading IOS 7.

FaceTime won't verify my main email address and can't use FaceTime over cellular network after downloading IOS 7. iPhone 4S, 32gb; AT&T says it's a problem with Apple. The AT&T tech rep tried everything he could to fix the problem. Can't delete the email addresses iOS 7 downloaded and it won't verify my main email address when added. FaceTime worked with my main email address over cellular network prior to iOS7 download.