Which cities receive the most robocalls

If it seems like you're getting more robocalls than ever these days, you're not alone.

Last month, American consumers were subjected to more than a billion unsolicited or automated calls, according to estimates from YouMail, which provides call blocking services.

"It's a huge time drain on American productivity, continually leads to fraud and crimes committed against unsuspecting citizens, and now appears to be rapidly getting worse," said YouMail CEO Alex Quilici.

Part of the surge is coming from the wide field of presidential candidates polling voters, said Quilici. Some of the biggest increases were logged in New Hampshire (up 70 percent from November) and Iowa (72 percent.)

If you're already had enough annoying cellphone calls from Rachel at Card Services, you may soon be hearing more from her, thanks to a tiny amendment in the federal budget. The provision ordered the Federal Communications Commission to set new rules allowing debt collectors to robocall cellphones to hunt down debtors and get them to pay up.

Debt collectors are already among the most active callers, which helps explain why they top the list of consumer complaints about robocalls, according to the Consumer Financial Protection Bureau.

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And, based on a CNBC.com analysis of over 50,000 consumer complaints to the CFPB related to debt collection, your cellphone may be targeted even if you don't owe anyone a dime. Roughly two-thirds of those that were related to debt collections were from people who had no debts. More than 21,000 consumers reported being harassed about debts that weren't theirs; 10,000 said the debt had been paid or discharged in bankruptcy. Some 2,200 said the debt in question was the result of identity theft.

In response to the wave of complaints, federal regulators have stepped up efforts to stem the robocall tide.

The Federal Trade Commission — which gets hundreds of thousands of complaints each month — has brought more than 100 against over 600 companies and individuals responsible for billions of illegal robocalls, according to the agency's website. About 80 have been resolved, generating over $41 million in civil penalties and $33 million in other payments.

In July , the FCC tightened rules against unsolicited calls. The provisions included stricter limits on what constitutes consumer consent to receive calls. The ruling also banned companies from calling numbers that have been reassigned to a new customer. It also widened the definition of an automated call and extended the ban on automated voice calls to apply to automated text messages.

That ruling faces a legal challenge from a debt collection trade group and other companies who argue that the ruling is too broad and prevents them from making legitimate calls to consumers.

But efforts to crack down on robocallers only go so far, largely because many of them are outside the reach of U.S. laws.

"It's a really tough problem, and it's not one that legislation alone is going solve because a lot of these robocalls originate from outside the country or they use autodialers and spoofing so they are very hard to find," said Ethan Garr, a product manager at TelTech Systems, which makes a robocall blocking app.

Major phone service carriers say they're also stepping up efforts to block annoying calls, but the task is made complicated by widely used "spoofing" tactics — in which robocallers, in effect, hijack a consumer's phone number and use it as the source of the automated call. Shutting down the robocaller could also mean blocking service to a legitimate customer.

One solution involves monitoring call traffic to identify suspicious spikes.

"Suppose we see (that) a mobile number that should be Verizon in some rural area has now called tens of thousands of times in 30 minutes," said Quilici. "There's no way an individual could dial tens of thousands of numbers in that short a time. So we know it must be a scammer."

Consumers may yet get the upper hand thanks to a series of cellphone apps and block services designed to thwart robocall scams. One of them, Nomorobo, got its start with the help of a grant from the FTC.

But even as blocking technology become more sophisticated, the most effective solutions may be the simplest.

"If someone does call you with a robocall, hang up immediately," said Garr. "That's the easiest thing you can do."