George Baiden usually avoids answering calls from numbers he doesn't know. But when a Toronto area code appeared on his cell, he picked up thinking it was a friend.

It turned out to be from an elaborate telephone scam whereby fraudsters steal phone numbers to make their calls — the latest twist in a long line of similar schemes that have bilked people across Canada out of millions of dollars.

The man on the line, Baiden says, was aggressive, claiming to be with the Canada Revenue Agency (CRA) and threatening legal action if Baiden didn't send him money.

"I asked him, 'Who are you and what's your employee number?' He said he couldn't give me that information, it's classified. So then I said to him, 'You're calling me, so why don't you tell me what my name is?' And he said … that I have to identify myself to him," said Baiden.

Baiden, left, sits with CBC reporter Thomas Daigle. On Tuesday, Baiden got a call from someone pretending to work for the CRA. (Craig Chivers/CBC )

After some back and forth, Baiden told CBC reporter Thomas Daigle the scammer got frustrated and hung up the phone.

Baiden called the number back and was puzzled when someone else answered and said they had never made the call. In fact, the Toronto man said he had missed a call from Baiden's number and was about to call him back.

Spoofing scams make millions of dollars

CBC Toronto spoke with the other man, who didn't want his name published. Both he and Baiden say they were confused when they realized the numbers the scammers had used were their own.

"I asked him if he worked for the CRA, he said, 'No, but these scammers are getting very sophisticated,'" said Baiden.

Callers masquerading as government agencies and using local numbers to do so is just the latest in telescam trends.

Scam artists have made tens of millions of dollars by using programs to spoof legitimate local numbers or even numbers belonging to government organizations, said Rhonda McEwen, an associate professor at the University of Toronto's Mississauga campus who teaches new media and communication,.

"This is a globally run business. These are massively well-paying jobs where people are actually doing this."

Rhonda McEwen, an associate professor at the University of Toronto's Mississauga campus who teaches new media and communication, says scammers are making millions by calling Canadians and demanding money. (Craig Chivers/CBC)

Since 2014, the Canadian Anti-Fraud Centre has received 78,472 reports from across Canada of scammers pretending to represent the CRA or Immigration, Refugees and Citizenship Canada. The centre says 4,695 people have lost more than $16.7 million.

The Canadian Anti-Fraud Centre has also received hundreds of complaints about spoofing scams, many of them requesting payments through gift cards or money transfers.

Don't trust your caller ID

According to the centre, that should be one of the first signs that something is off. In a recent public handout, the centre wrote no government service, including the CRA, "would request payment by a money service business, iTunes or bitcoin."

The centre also warns against relying on your caller ID, saying "it's a service of convenience, it's not a secure feature" that identifies who is on the other end of the line.

The country's top service providers are working to block spoofed calls by Dec. 19. The move is in response to a directive issued last year by the Canadian Radio-television and Telecommunications Commission (CRTC), telling companies to reduce the number of nuisance calls Canadians receive.

Bell and Rogers, for instance, are testing new, universal call-blocking technology at the network level.

McEwen said the improvements can't come soon enough.

"People are very careful about answering that mobile device. It's actually in the interest of the providers and the device manufacturers to help users deal with this, otherwise people will start using other channels … You don't get this through WhatsApp or any other messenger channels."

Until then, McEwen advises people to put themselves on do-not-call lists and block any recurring, threatening numbers.