2727 Mahan Drive. Tallahassee, FL 32308. 1-888-419-3456. The Joint Commission. One Renaissance Blvd. Oakbrook Terrace, Illinois 60181. 1-800-994-6610. complaint@jointcommission.org. If you are covered by Medicare, you may choose to contact the Medicare Ombudsman at 1-800-MEDICARE (1-800-633-4227) or on line at www.Medicare.gov..