The Federal Communications Commission issued a $300 million fine - it's largest ever - against a robocall operation offering extended vehicle warranties.

The FCC earlier had devised a plan with cell phone companies to block five billion of the unwanted calls, according to FCC Chairwoman Jessica Rosenworcel. It helped decrease the number of auto warranty calls by 99%.

"At one point, it seemed like these calls were everywhere. They were more than just a nuisance. That’s because this scheme flooding our lines marketing fake car warranties was part of a scam to gain access to our personal and financial information," FCC Chairwoman Jessica Rosenworcel said in a prepared statement.

She said the fine, announced in early August, was the commission's largest.

What is the auto warranty scam?

The scam involves a person posing as car dealer representative, manufacturer or insurer telling you that your auto warranty or insurance is about to expire and that you need to renew, according to the FCC.

It's usually an automated or pre-recorded call that asks you to press a number or stay on the line, and then asks for personal information. The FCC warns that scammers can deceive people into believing the offer is real because the robocall often has specific information about your make or model of car.

Who was behind the robocalls?

The investigation centered on central people who were already under lifetime bans from making telemarketing calls − Roy M. Cox and Aaron Michael Jones.

Both did business under Sumco Panama, Virtual Telecom, Davis Telecom, Geist Telecom, Fugle Telecom, Tech Direct, Mobi Telecom, and Posting Express and operated the scheme since 2018, FCC officials said in a press release.

They added that the companies violated federal statutes and FCC regulations when they made the calls in 2021− five billion robocalls to more than 500 million phone numbers in three months.

They also violated federal spoofing laws by tricking victims into answering the phone by using more than a million different numbers, a multitude of robocall prohibitions by making pre-recorded voice calls to mobile phones without prior consent, placed telemarketing calls without written consent, dialed numbers from the National Do Not Call Registry, did not identify the caller at the start of the message, and didn't provide a callback number so consumers could opt-out of future calls.

The FCC imposed the fine for $299,997,000, and offered Jones and Cox a chance to respond, which they did not. If they do not pay the fine, FCC officials will refer the case to the U.S. Department of Justice for collection.