But this scam complicates even that strategy.

With our phone lines saturated with robocalls, many people only pick up if they recognize the number.

Lluis Gene | AFP | Getty Images

Rebecca Schulte, 24, was at her apartment in West Hollywood, California, when she received a call from a familiar area code. She picked up. "I'm on the side of the road, there's been a really bad car accident," a man said. He told her he'd found her number in the injured man's phone. Rebecca knew her father had been driving, and in a panic she asked if it was him: "Is it Brian?" "Is your name Brian?" she could hear the man ask.

If this problem isn't solved, we're getting close to the death of the phone call. Jonathan Nelson director of product management at Hiya

He told her it was. "He's bleeding a lot," he added. Then, the man told her that if she didn't send him money immediately he would let her father die. "I stopped mid-sob," she said. She suspected it was a scam and hung up. Still, many people do end up sharing financial information over the phone. More than $9 billion was lost from phone scams in 2017, up from $7.4 billion in 2015, according to a company that tries to combat such issues, Truecaller. More than 7 million complaints were filed with the National Do Not Call Registry last year, according to the Federal Trade Commission. "Phone scams are one of the big problems right now," said Adam Doupe, associate director of the Center for Cybersecurity and Digital Forensics at Arizona State University. "They're much more effective than email scams." The growth of the phone scam is, in part, thanks to a new tactic these criminals are using that makes people more likely to answer their calls, and then trust them once they do. Scammers are increasingly spoofing phone numbers to make them look familiar to you. They might use your area code or the first six digits of a friend's phone number. Half of all phone scams today use this tactic of digit spoofing, according to a recent analysis by Hiya, a phone spam protection company.

Now most people's primary line of defense against these dangerous calls — to simply not pick up the phone if they don't recognize the number — is being challenged. "One of the key flaws in the current telephone system is this fact that spammers can spoof the caller ID," Doupe said. He said older people are especially at risk. "The phone is their main form of communication," he said. "When they get a scam call, they're more likely to take it at face value."