With your supplier or with Medicare
You may file a complaint with your supplier, or call 1-800-MEDICARE.
The supplier must let you know they received your complaint and are investigating it within 5 calendar days.
Within 14 days, the supplier must send you the result and their response in writing.
With the Competitive Acquisition Ombudsman
Your complaint may also be referred to the Competitive Acquisition Ombudsman. The Competitive Acquisition Ombudsman responds to individual and supplier inquiries, issues, and complaints. The Ombudsman reviews the concerns raised by people with Medicare through 1-800-MEDICARE and through your State Health Insurance Assistance Program (SHIP).
For questions about a specific service you got, look at your Medicare Summary Notice (MSN) or go to MyMedicare.gov. If you disagree with a coverage or payment decision made by Medicare, your Medicare health plan, or your Medicare Prescription Drug Plan, you can file an appeal.