DELRAY BEACH, Fla. — Nearly a year after my first visit to the Delray Beach office where Sunshine Senior Solutions is headquartered, I went back. The paper sign that had been on the door was gone, and unlike the last time, no one answered when I knocked.
WATCH BELOW: 'Billions of billions of dollars going to waste and fraud,' Dr. David Maimon tells WPTV's Jamie Ostroff
The phone number for the business, which previously went to the voicemail of a woman named Sherry, had been disconnected. So had the phone number for the person currently listed in business filings as the owner of Sunshine Senior Solutions.
Carolyn Brovero of Hobe Sound is one of dozens of seniors nationwide who contacted me, saying she received Medicare statements from Sunshine Senior Solutions for medical equipment she didn't need. She showed me her Medicare statements with thousands of dollars in charges for hundreds of catheters and five prosthetic devices.
“Which I did not order, did not receive, I never heard of never heard of the doctor whose name was on it,” Brovero said.
WATCH BELOW: 'I am more interested in the money than the criminal,' Dr. Mehmet Oz tells WPTV Chief Investigator Jamie Ostroff
Since I started looking into Sunshine Senior Solutions last year, beneficiaries who shared their statements with me reported nearly $400,000 in charges to Medicare they say they never authorized. Their gap insurance flagged the charges as suspicious and did not pay the leftover balances.
Dr. David Maimon is a fraud expert who teaches at Georgia State University. He calls himself “The Undercover Professor” online, because of his ability to infiltrate fraud operations to learn more about them.

“It's mind boggling to see how sophisticated this operation is,” Maimon said.
After learning about Sunshine Senior Solutions earlier this year, Maimon traveled to Delray Beach to see the office for himself.
“They were simply gone,” Maimon said.
WATCH: Seniors from across the country spoke to WPTV about Delray Beach company
Maimon featured the business prominently in his new report: "How Floridians Identities are Being Used to Fuel Medicare Fraud." The report details what Maimon calls the "large-scale harvesting, sale and reuse of beneficiary identities" to "extract taxpayer dollars at scale."
“Billions of billions of dollars going to waste and fraud,” Maimon said.
Maimon’s report includes examples of how identities are stolen through large healthcare data breaches or phishing scams.
“Once they have all the information, the criminals are essentially offering this for sale on platforms such as Facebook. (One) vendor offered to sell me a bunch of Floridian identities, including Medicaid and Medicaid numbers for as low as $10 per identity,” Maimon said. “And what the fraudsters do is essentially use some of the numbers and identities that they see out there and use them to charge the program."
PREVIOUS COVERAGE: Seniors question Medicare charges from this Delray Beach company
Through his undercover investigation, Maimon discovered people who had complained publicly on social media about Sunshine Senior Solutions had experienced multiple identity theft attempts before getting those Medicare statements.
Maimon said Medicare fraud is more prevalent in Florida for three reasons: the large population of Medicare beneficiaries, a high concentration of legitimate healthcare businesses that make it easier for phony businesses to blend in, and a history of organized healthcare fraud in the state.
Maimon has called on the state and federal governments to perform more due diligence when someone tries to set up a healthcare business.
I am still trying to get ahold of someone from Sunshine Senior Solutions to comment on Maimon's findings.

Back in Hobe Sound, Brovero said she recently received a new Medicare number.
When asked if the experience changed her approach to unsolicited text messages or mail asking for information, Brovero said she continues to keep a watchful eye.
“Oh, I always delete (those texts), but I always did anyway. I can show you one I just got yesterday if you want to see it!” Brovero said.
Brovero urged her fellow beneficiaries to read every Medicare statement from top to bottom.
“What can we do? We have to be vigilant,” Brovero said.
This story was reported on-air by a journalist and has been converted to this platform with the assistance of AI. Our editorial team verifies all reporting on all platforms for fairness and accuracy.
Read more of WPTV's coverage below:
WPTV Investigates
Reports to Medicare surge against Delray Beach medical supplier
WPTV Investigates
Seniors question Medicare charges from this Delray Beach company
WPTV Investigates
'I want the money stopped': Medicare chief on fraud allegations against company
State