The new PO Box for Highmark Medicare Services Provider Enrollment (890036) will not be activated by the Post Office until November 14, 2008. It has come to our attention that a few customers have sent EFT Authorization (CMS-588) forms to this post office box and the mail has been returned to them. If this has happened to you, please re-send your information on November 14, 2008. We will be sure to take this into consideration when processing your application.