http://getirshelp.com - The IRS Form CP504b is a form used by the Collection Division of the Internal Revenue Service. A taxpayer gets this form in the mail when they have a balance due and after repeated demands have not paid the balance in full.The Law Office of Darrin T. Mish 15421 N Florida Ave Tampa, FL 33613‎ (813) 229-7100 http://GetIRShelp.com