Best of all, it’s cheap: VoIP services cost three-fifths of a penny per minute, and that’s only if the call is answered. Unscrupulous carriers openly advertise their services to those looking to make “dialer/short duration termination calls”—the jargony euphemism for robocalls—and databases of consumer phone numbers are easy to buy. “The technology has gotten so inexpensive that any person can become a robocaller overnight,” says Ian Barlow, who coordinates the FTC’s Do Not Call program. “It’s easy, it’s accessible, and there are no barriers to entry.” Once the software has been programmed to control who to call and when, the robocaller doesn’t even need to press a button to start making calls each morning. The same technology also makes scammers hard to identify and track down.

Little wonder, then, that the United States is awash in robocalls. According to YouMail, a maker of robocall-blocking software, Americans received a record-breaking 47.8 billion robocalls in 2018. That works out to nearly 200 per year for every adult. Unwanted calls are the most common consumer complaint lodged with the Federal Communications Commission, and the trend shows no signs of slowing, despite the pile-on of laws and regulations—the Telemarketing Sales Rule, the Truth in Caller ID Act, and the Telephone Consumer Protection Act, among others—outlawing the vast majority of auto­dialed calls or prerecorded messages, at least those used for marketing purposes. With more than 100 million calls placed every day, robocalling might well be the most ubiquitous, most hated, and least punished crime in the country.

Garvin set up shop in a quiet corner on the third floor of TripAdvisor’s headquarters, flanked by whiteboards and a bay of screens, preparing to track down the mystery robocaller. Garvin is in his early forties, with dark, spiky hair, a soft face, and darting eyes. In conversation, he is calm and self-possessed, even formal, but he buzzes with a tightly wound energy.

Garvin scoured the web, looking through blogs, forums, and social media for any mention of a similar call. He didn’t have to look very far. Dozens of people were grumbling—or worse—on TripAdvisor’s own forums. “IF I EVER GET A CALL LIKE THAT AGAIN, I WILL CONTACT THE FCC AND I WILL OPEN THE GATES OF HELL ON TRIP ADVISORS,” one person wrote. “NEVER NEVER NEVER NEVER CALL ME LIKE THAT AGAIN. EVER. GOT IT.”

One of his early gambits was simply calling a number that had placed a robocall. When he tried that, though, he found a human on the other end of the line, perplexed as to how their phone number had been used for prerecorded marketing. Eventually he figured out that the robocaller was engaging in a practice called neighbor spoofing—making the calls look as if they were coming from someone living near the intended recipient. For Garvin, it was a dead end.

Hoping he might get lucky and receive one of the robocalls himself, Garvin began answering every suspicious call and spoofed number that lit up his cell phone. He heard dubious alerts about student loan forgiveness, unclaimed lottery windfalls, and tax debt. “I was the only person you will ever meet who was excited to receive a robocall,” he says. He was getting several a day and answering as many as he could, all the while hoping for one that would lead back to the TripAdvisor scam.

The irate stories on TripAdvisor forums seemed like promising leads, except that the details didn’t line up. People who got the same prerecorded pitch on the same day were transferred to live operators who offered different vacation packages at different prices. Garvin and Young felt as if they were “chasing ghosts,” Young said.

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Those posts did offer a few clues: The calls came over VoIP and seemed to be a classic bait and switch. If you were on the line, you’d hear a recorded female voice saying that you’d received TripAdvisor credits that could be redeemed for a vacation. The “credits” might be for $999 or $2,000—the amounts differed—but you’d be instructed to press 1 to take advantage of the incredible offer and then be transferred to a live operator. Neither the credits nor the name Trip­Advisor would be mentioned again. Instead, the operator would pitch an unrelated offer: a cruise, a resort, an all-inclusive stay at a beachfront hotel.