If you want to login to your FAFSA application, but you have forgotten your username, go to fsaid.ed.gov. Enter your email, or phone number. Then select Forgot My Username. If that doesn't fix the problem, contact FAFSA at 800-433-3243 - seven days a week and request Customer Service to talk with a live assistant . You can also email [email protected] or call her at 801-826-6312.