On average, Americans received more than 2,000 robocalls every second in October, up 25% from the previous month. With 49 billion robocalls so far this year, all four major U.S. phone carriers now offer some form of blocking or screening service. T-Mobile, for example, uses a "Scam Likely" label. Congress and state officials passed new robocall regulations in recent months and have seen an uptick in successful cases against the scammers. Meanwhile, hundreds of tech start-ups are developing new ways to tackle the problem.

Watch the video to see how robocalls work and what's being done to stop them.