Foreign telemarketing firms are "harassing" Canadians on the federal do-not-call list, and the CRTC is powerless to stop them, a CBC investigation has found.

In an undercover investigation, Marketplace brought hidden cameras into a Karachi, Pakistan, call centre that sells air duct cleaning services to Canadian households. Undercover footage captured a supervisor telling employees to lie to customers, saying there is "no need to worry" about Canada’s do-not-call list (DNCL), which is meant to protect Canadians from unsolicited calls.

As a result, some Canadians face constant pestering from the same companies and are feeling helpless.

Marketplace spoke to several frustrated victims and has withheld their last names to protect their privacy and prevent further harassment from the aggressive telemarketers.

They’re angry at the callers and the CRTC, which can’t do much to stop them.

"I feel as though I’m losing grip on reality, and losing control," Heather said. "You say, ‘no, no, no, thanks.’ And then eventually you say , ‘F--k you.’ And it still doesn’t work."

"Please, somebody out there, please start taking this seriously."

Fake numbers, fake names

Someone is taking it seriously, says CRTC compliance and enforcement chief Andrea Rosen. But these telemarketers use a technical trick called "spoofing," which fools caller ID into displaying a different number than the one actually calling. That makes the telemarketers hard to catch.

CRTC compliance and enforcement chief Andrea Rosen says the agency has limited power to stop fraudulent telemarketing calls from outside Canada. (CBC)

"The problem with (spoofing) … is that it's very difficult to detect who those people are and find out where they're calling from," Rosen explains. "If we can’t find them, we can’t act."

The call centres are confident that they’re untraceable, too.

In Marketplace’s undercover investigation, a Karachi call centre supervisor was caught on camera reassuring a new hire that they can’t be caught.

"There is no need to worry," he says. "The customer will not be able to report us. They can’t trace us."

Employees are also told to say they’re calling from Ontario, and the callers used fake names.

Being so well hidden, the telemarketers have little to fear, and that impunity can lead to vicious harassment.

Andrew’s wife got a taste of that when she tried to complain to one call centre.

"The telemarketer said that [my wife] would be able to speak to this person’s manager if she sucked his d--k," Andrew said.

"Sexually harassing people over the phone? That’s disgusting," he added.

He and his wife filed a police complaint over that call, but got no results.

CRTC largely powerless

That’s another problem: Canadian authorities can’t make it stop.

"If you’re the CRTC, how can you let this keep going on?" Andrew asked. "You have so much power to prevent this kind of activity and yet you’re doing nothing. Stop these calls. Work for the citizen."

Watch Marketplace's episode, To Catch a Telemarketer, Friday at 8 p.m. (8:30 p.m. in Newfoundland and Labrador).

The CRTC does have a little power, but only with companies it can find. In October 2012, it fined two Indian software companies a total $507,000 for calling Canadians registered on the DNCL. Rosen says the CRTC has imposed $3 million in fines since 2008 for similar violations. The difference is that the software companies weren’t concealing their identities.

The spoofing call centres are beyond the CRTC’s reach, Rosen says.

"No one has the power of changing anything when spoofing is in play," she adds. "I don't care who the agency is. There's no way to determine who the person is that's calling and from what location, if the number is spoofed."

However, she encourages Canadians to lodge complaints so other agencies might take action.

"The do-not-call list is not their only avenue," she said. "The Canadian Anti-Fraud Centre is their avenue, the police is their avenue, the Competition Bureau is their avenue, and these should use every opportunity to see whether or not something can be done."

‘Use it or lose it’

The DNCL is not an avenue at all when it comes to these questionable firms, Rosen says, because they don’t even use it. Legitimate telemarketers are supposed to register and subscribe to the DNCL. The spoofers don’t bother.

"They're not using the do-not-call list," Rosen explains. "They're just calling everybody they can to identify people who will answer the phone and talk to them."

Even when the authorities can identify the callers, there’s no guarantee they can make the calls stop. The CRTC has no jurisdiction outside Canada, so even in cases where it has levied fines, the offenders can’t be forced to pay up.

Rosen says the CRTC is working with other countries to develop an international network that can more effectively track and penalize fraudulent call centres.

But until then, fraudulent call centres can continue to operate freely, leaving Canadians frustrated and helpless.

"In my opinion, the do-not-call list is not working at all," Heather said. "Use it or lose it."

Watch Marketplace's episode, To Catch a Telemarketer, Friday at 8 p.m. (8:30 p.m. in Newfoundland and Labrador).