Online Feedback and a Phone Call
The National Football League runs a comments section on its website where you can file a complaint. Unfortunately, complaints are for the website only; not the NFL as a whole. Your best bet is to mail a printed or handwritten complaint to the league office at 345 Park Ave., New York, NY 10154. You can also file a complaint directly with specific teams. Go to the team's website and look for a comments, contact or feedback section to leave an online complaint. Or keep digging for an office address or phone number for a more personal form of communication.