Enrollment Options 2023 Medicare Supplement Plans ("Medigap") Medex Core, Medex Sapphire, Medex Bronze Enroll Online You can enroll in a Medicare Supplement Plan at any time throughout the year. Enroll Now Call Consumer Sales 8:00 a.m. to 5:00 p.m. ET, Monday through Friday Call 1-800-678-2265 TTY: 711 Mailing Address Consumer Sales Blue Cross Blue Shield of Massachusetts One Enterprise Drive Quincy, MA 02171-1754 Enrollment Forms Medex Core, Medex Sapphire, Medex Bronze Enroll through Fax 1-617-246-8506