If you lose or damage your Medicare card, you can obtain a replacement card from Social Security one of the following ways:
Order Online by visiting the Medicare Card Replacement section of Social Security's Web site. You card will be mailed within 30 days to the address SSA has on record.
Their Online business hours are: Monday - Friday: 5 a.m. until 1 a.m. Saturday: 5 a.m. until 11 p.m. Sunday: 8 a.m. until 10 p.m. Holidays: 5 a.m. until 11 p.m.
If you need proof right away that you have Medicare, contact your local Social Security Office or call the toll-free number at 1-800-772-1213. The people there can give you proof that you can use until you get your replacement Medicare card.
To get a replacement, you need to contact your state Medicaid office and report the incident. The card will arrive in the mail in about 30 days to the address that the social security have in record. Learn more from https://secure.ssa.gov/apps6z/IMRC/main.html.