You answer the phone and you’re greeted by a weird tone, followed by a few seconds of silence.

Then comes a voice saying “I’m with Health Care Benefits” or “Medicare Services” or something else equally as generic.

The voice promises to improve your Medicare benefits, possibly save you money, or even get you more money in your Social Security check. “Hold on to be transferred to one of our agents,” the caller says.

Your phone displays a local number, “spoofed” to make you think it’s someone you know. Perhaps your phone displays the words “Potential Spam.” Then there are odd beep, clicks and call center chatter in the background.

Is it a spam call intending to trick you into giving your birth date, Social Security number, bank account number, so some oversees crooks can steal your money?

Possibly, or it could be a scam cloaked in legitimacy.

Chances are good the registered agent who comes on the line next works for an actual health insurance agency that can switch you into a Medicare Advantage plan that's very different than the one you have now. Those plans have multiple variations and the agent might not disclose an inferior plan's limits and won't necessarily get your permission to make the switch.

According to Medicare experts and a new study released last week by the Senate Committee on Finance, the inferior plan could leave you without a prescription drug benefit, or omit your favorite doctors from your available in-network providers. And you won't find out until it’s too late to change back.

The agencies work with lead-generation companies that are bombarding older people in Florida and across the country with unsolicited and possibly illegal solicitation calls, according to independent health insurance agents and telemarketing experts.

The unwanted calls began weeks before this year's Medicare Advantage enrollment period began on Oct. 15 and they are continuing as the days count down to the Dec. 7 deadline.

According to YouMail, a screening service for unwanted calls, at least 100 million Medicare-related robocalls were detected in October from more than 100,000 phone numbers, real and spoofed.

“This is likely to try to get their calls through various spam filters, whether the carriers’ or third-party (filter) apps,” says Alex Quilici, YouMail's CEO.

“It’s very annoying,” says Mindy Koch, a Boca Raton senior who says she started getting the calls three months before the enrollment period began.

“When they call me, I ask them, ‘What is your company’s name?’ They tell me and I go, ‘Perfect. I’m going to turn that in with your phone number to the Medicare Hot Line.’”

More and more Medicare Advantage consumers are filing complaints to the toll-free Medicare line — 1-800-MEDICARE — and other agencies, according to a report released Thursday by the Senate Committee on Finance.

The report, based on information compiled by the federal agency that runs the Medicare program, the Centers for Medicare & Medicaid Services, criticizes shady and misleading business practices by health insurance agencies licensed to sell Medicare Advantage plans.

Those agencies rely on what are known as lead-generation services to identify qualified prospects, the report says. Those services, which use television and print advertising as well as telemarketing and robocall dialers, are often inundating Medicare beneficiaries with “aggressive marketing tactics as well as false and misleading information.”

One reason the agencies are able to deceive consumers is that Medicare, for many, has become complicated to understand. To start with, there are three main kinds of Medicare plans:

“Original” Medicare: This consists of Parts A and B. Part A covers hospitalization and stays in skilled nursing facilities. It’s free for anyone who qualifies for Social Security, even if they haven’t claimed it yet. Part B is the portion that provides standard health insurance, such as doctor visits, outpatient services that do not require hospitalization, lab tests, flu shots and physical therapy. Members pay a monthly premium that's automatically deducted from their Social Security checks, if they get one. Currently the premium is $170.10 and will go down to $164.90 in 2023.

Part C: This is Medicare Advantage. Unlike Original Medicare, Medicare Advantage plans are run by private health insurers, often but not always the same large insurers that provide employer-sponsored health insurance and individual coverage that we know as Obamacare. Medicare Advantage plans combine Parts A and B with Part D, the prescription drug benefit that would otherwise require an additional monthly premium.

Like private insurance, Medicare Advantage plans can offer coverage not provided by Original Medicare, like fitness programs, some vision, hearing and dental services, transportation, and over-the-counter drugs, and can also be tailored to specific chronic conditions. They also may have networks of providers in members' local areas that they can visit for lower co-pays.

Unlike Original Medicare, Medicare Advantage plans have yearly limits on members' out-of-pocket cost for Parts A and B services. Once those limits are reached, members pay nothing for the remainder of the year.

Seniors who choose a Medicare Advantage plan still must pay for Medicare Part B. According to the nonprofit Kaiser Family Foundation, 69% of Medicare Advantage enrollees pay no supplemental premiums for the add-on services, while average monthly cost for the remaining 31% is $58 for 2022 plans.

The Senate Finance Committee report found that shady agencies use the complexities of the Medicare system to their advantage when they get a willing prospect on the line.

It summarizes results of an inquiry triggered by marketing complaints in 14 states, including Florida. CMS received 39,617 complaints about false and misleading marketing in 2021 — more than twice as many as the 15,497 received in 2020, the report says.

The report found numerous examples of "fraudulent and misleading practices":

• Marketing companies that use the word "Medicare" in their names or brands to suggest they represent the Medicare program. "These practices are intentionally deceptive as they blur the lines between official government communication and private health plan marketing," the report states.

• Agents were found to sign up beneficiaries for plans under false pretenses, including saying that coverage networks include preferred providers even when they do not. In some cases, agents changed plans of "vulnerable" seniors and people with plans tailored to their disabilities without their consent. Under the new plans, those seniors can experience higher out-of-pocket costs and difficulties accessing their longtime doctors.

• Promises to increase seniors' Social Security checks were a frequent source of complaints. Medicare Advantage plans sometimes pay parts of enrollees' Medicare Part B premiums, which allows members to keep more of their Social Security payments. But the report found those promises are often used as "bait and switch" come-ons. Other times, consumers find that extra money is offset by reduced services and access to fewer providers.

In one example cited in the report, an Oregon man agreed to switch to a plan after an agent told him he could get an extra $135 a month in his Social Security check. It wasn't until he went to his pharmacy to fill his prescription that he learned his new plan did not include Part D, which covers prescription drugs. According to the man's complaint, the agent failed to disclose that he would lose his drug benefit.

Ron Hurtibise writes for the South Florida Sun Sentinel.