If you think a mistake has been made in a bill, call your doctor, hospital or other provider first. It may have been a simple, honest error.

If the provider’s answer does not satisfy you, and you are in Original Medicare you can call the company that paid the Medicare bill. You can find the number for the company on your Medicare Summary Notice (MSN) or by calling Medicare at 800-MEDICARE (800-633-4227) and asking for the number. A Medicare Summary Notice is a summary of claims that Medicare processed for you within the last 3 months. It is not a bill.

If the provider’s answer does not satisfy you, and you are in a Medicare Advantage plan, like an HMO or a PPO, you should contact your plan. You can find the phone number for the plan on the back of your Medicare Advantage plan card. Your Explanation of Benefits should also include the plan’s phone number. An Explanation of Benefits is the notice your plan sends you when it has processed a claim for you. It is not a bill.

Whether you receive your Medicare benefits from Original Medicare or a Medicare Advantage plan, you can also call the Inspector General’s fraud hotline at 800-HHS-TIPS (800-447-8477) to report fraud.

When investigating the potential fraud, Medicare will not use your name if you do not want it to.