Most $250 rebate checks should have been mailed out by March 15, 2011, so you might want to be careful with any rebate checks that are just now arriving in the mail. When in doubt, please call Medicare at 1-800-633-4227 to be sure that your Donut Hole rebate check is authentic.
Unfortunately, Medicare provided a description of the envelope containing the $250 rebate checks, but not a description of the checks.
Medicare noted in an earlier publication: "The [$250 rebate check] envelope will have the US Department of Health and Human Services symbol on it and will say ‘Medicare Part D." Medicare also cautioned that: "[y]ou don't need to provide any personal information like your Medicare, Social Security, or bank account numbers to get the rebate check. Don’t give your personal information to anyone who calls you about the $250 rebate check."