What is cms contact number? The customer support phone number of CMS is +1-410-786-3000 (Click phone number to call). The postal and official address, email address and phone number (helpline) of CMS Service Center and CMS customer service phone number is given below.What is the telephone number for cms? The CMS Certification Number (CCN) is the organization's Medicare Provider Number and is required for users associated with an organization to access the Provider Statistical and Reimbursement (PS&R) application portal. If you do not have this information, please contact your Medicare Administrative Contractor (MAC).What is cms certification number or ccn? To put it in layman’s terms, an intranet is your company’s internal website, used by employees to communicate with each other, and access the information needed to perform their daily jobs. CMS (short for Content Management System) is the platform which manages your website’s content.