If you're still working your way through a backlog of mail you received over the holidays, don't be surprised to see a revalidation letter that isn't yours. But that doesn't mean you're off the hook for revalidating. HHH MAC CGS mailed revalidation letters dated Dec. 20, 2011, to all HHAs with a Provider Transaction Access Number (PTAN) beginning with 01 through 29, the MAC explains in an e-mail to providers. Letters were mailed to the provider's special payments address. Oops: Just to make doubly sure, CGS also mailed a second letter to the provider's practice location address. But those letters were accidentally mailed to the wrong address, CGS says. CGS re-sent the letters to the correct address the last week of December. "Therefore, there is no need for providers to contact CGS to report that they received another provider's letter," the MAC advises.