Above video: Family describes con artists who stole much of mother's life savingsAfter a year of relief, robocalls are back up to pre-pandemic levels.Americans received more than 4.6 billion robocalls in February, up 15% compared to January, according to new data from YouMail, a robocall-prevention service that tracks robocall traffic across the United States. About 159.1 million robocalls were placed each day last month.This marked the highest monthly robocall volume since February 2020, notably right before the COVID-19 pandemic hit the United States hard. So far, 2021 is on pace to reach 51.5 billion robocalls, a big jump from 2020 (45.9 billion). Americans received 58.5 billion robocalls in 2019, up 22% from the year before."Because February was a short month, I think the first two months are lower than we'll see going forward and we're actually going to wind up much closer to 2019's pre-pandemic levels overall," YouMail CEO Alex Quilici told CNN Business, attributing the resurgence to economies' reopening worldwide.Americans experienced a significant drop in the amount of robocalls flooding their phones last spring, helped by international call centers being shut down during the global pandemic and government efforts to stop COVID-19-related scams. At the time, YouMail reported the number of robocalls made to U.S. phone numbers in April was the lowest in two years. That included both scam and legitimate calls, such as payment reminders from banks."Call centers are closed or running at much lower capacity due to social distancing around the world," Quilici told CNN Business at the time. "There's no point to robocall people if there's no one there on the other end when someone 'presses 1' or returns a call."The latest report noted that scam and telemarketing calls accounted for about 60% of last month's robocall volume — a trend in line with past months. The leading illegal types of robocalls involved car warranties and health-related scams.

Related video above: How cellphone scams can happen to youThe scourge of obnoxious robocalls has resumed after a brief dip during the early months of the pandemic.But a new prevention program developed by the Federal Communications Commission — which officially went into effect this week — could begin to offer some relief later this year.The program, called "Stir/Shaken," is a set of technical standards that mobile carriers are required to adopt to help prevent call "spoofing," a tactic used by robocallers to make an incoming call look like it's from your area code so you're more likely to pick up. Robocalls from spoofed numbers aren't just an annoyance, they're dangerous — capable of scamming people out of money or sensitive personal information such as Social Security numbers.Under the Stir/Shaken protocol, carriers are required to certify, with varying confidence levels, that calls really are coming from the numbers displayed on caller ID. The deadline for most big carriers to implement the standards was Wednesday and the major carriers have all said they've signed on.The idea is this: When your wireless carrier processes an inbound call that doesn't have a certification letting it know the number is legitimate, the carrier will be able to block it before your phone ever starts ringing."While there is no silver bullet in the endless fight against scammers, Stir/Shaken will turbo-charge many of the tools we use in our fight against robocalls," FCC acting chairwoman Jessica Rosenworcel said in a statement Wednesday.But don't get too excited just yet. Experts say Stir/Shaken won't be an automatic fix to the millions of robocalls that are placed in the United States each month.For one thing, carriers won't actually start blocking calls based on the Stir/Shaken verification information until Sept. 28. In the meantime, they'll gather information about which calls are and aren't certified in an effort to avoid blocking calls that someone actually wanted to receive, according to Ed Fox, chief technology officer at network services firm MetTel. For example, carriers want to avoid accidentally blocking an automated message from your hairstylist reminding you of an upcoming appointment.Until then, consumers of some carriers may see an indicator that the number has been verified (or not) when receiving a call, so they can decide whether to pick up.Carriers have "had to come up with a mitigation plan that hopefully prevents blocking legitimate calls," Fox said. "There will be a lot of challenges, but toward the end of October, we'll see significant drops in some of that robocalling."While major carriers have implemented Stir/Shaken, the FCC granted carriers with 100,000 or fewer subscribers a two-year extension to adopt the standards, meaning bad actors could rely on those carriers to continue doing call spoofing in the meantime. Some small carriers have other robocall mitigation plans to prevent outgoing scam calls from their network, but they may not work as well as adopting the new standards, said Alex Quilici, CEO of YouMail, a company that tracks robocalls and offers a call blocking app for consumers.Another potential challenge: Bad actors could simply purchase legitimate phone lines that will show up as "verified" by carriers and make robocalls from those. While this would require bad actors to take extra steps — and therefore will likely be used less often than existing "spoofing" methods — it could make for more dangerous robocalls, said Quilici.For example, if someone receives a call that shows up as verified, and a scammer on the other end says they're a representative of a bank or big retailer, the recipient may be more likely to believe them and give up personal information."I think people are going to be really disappointed to find out that really what's happened here is a speed bump, not a wall" for bad actors, Quilici said.