The Medicare fee-for-service program, the nation‚ is largest health insurance plan, is administered by private organizations under contract to the Centers for Medicare & Medicaid Services (CMS).
Called Medicare administrative contractors (MACs), they enroll providers, educate them about coverage and appropriate billing, answer beneficiary and provider inquiries, and detect fraud and abuse. Their primary task, however, is prompt and accurate payment of the 1.2 billion claims submitted yearly for Medicare-covered services.
The MAC800 app is for healthcare providers. This apps lists by state and program the various customer service and interactive voice phone numbers.