Con artists and scammers are constantly inventing new ways to take advantage of elderly people.

The Medicare Open Enrollment Period offers the perfect opportunity to dupe seniors. Identity thieves are targeting Medicare recipients for their personal and financial information, then running up huge bills in their names before anyone is the wiser.

Below are some common scams that target seniors during the Medicare Open Enrollment Period and information that will help you to avoid each one.

Scam 1

An "official Medicare agent" knocks on a senior's door. The agent says she's selling Medicare insurance that can save the senior thousands of dollars in healthcare costs next year. The offer is only good during Medicare's Open Enrollment Period.

Fact: There are no Medicare sales representatives. Ignore cold calls. If you haven't asked for an agent to contact you, federal law prohibits an agent from trying to sell to you—whether it's a phone call, an e-mail or a knock on your front door. If an agent tries to sell you something on behalf of Medicare, you should report that person to authorities.

Scam 2

A senior receives a call that says they must have a prescription drug coverage plan or they will lose their other Medicare benefits. If the senior doesn't join a plan during enrollment time, their Medicare benefits will be terminated.

Fact: If someone says you must join or you'll lose your other Medicare benefits, it's a scam. The Medicare prescription drug benefit is voluntary. It supplements your other Medicare benefits.

Scam 3

A senior gets a call from someone claiming that the senior Medicare recipient is owed a $250 refund because they've reached the prescription drug coverage gap known as the "donut hole." The senior is asked to provide her birth date, Social Security number, bank account and Medicare numbers so the refund can be automatically deposited into her checking account.

Fact: Medicare will never call and ask for your Medicare or social security number. No senior should ever give their Medicare number to any caller. Guard your personal information. Treat Medicare, Medicaid and Social Security numbers like a credit card number, and never give these out to a stranger. If someone claims to be with Medicare and asks for your information, ask for their name and report it to 1-800-MEDICARE.

Scam 4

A senior receives some official-looking brochures about new Medicare products that available at a discounted price during Medicare open enrollment.

Fact: Don't be fooled by sales materials that look like they're from the government. Con artists often try to impress consumers with official-looking sales materials that look like they're from a government agency. Private companies – not the government – sell Medicare Advantage and Medigap plans. Be skeptical of promotional materials claiming to come from the government.

One Last Thing

Medicare beneficiaries need not (and cannot) enroll in health insurance plans on the Health Insurance Marketplace created by Obamacare. No one is allowed to attempt to sell a Marketplace plan to an individual who already has Medicare.