The next time another unknown number unexpectedly rings your phone, send it straight to voicemail.

That’s the safest way to weed out a legitimate caller from the scammers that spammed Americans with more than 29 billion robocalls last year that cost consumers $350 million.

And it’s getting worse.

Spam call blocking service YouMail reports that 2.5 billion robocalls blew up our phones in April alone, with the average person getting 7.7 unsolicited calls. That’s a 13.6% increase since just last February.

Plus, clever con artists often try profiting off of topical subjects, like calling about donations following a national tragedy, so tax season the past couple of months has likely spurred a slew of phony IRS and debt collecting calls. They phish for your personal information, or get you to agree to buy shoddy products and accept fraudulent charges. And the Federal Communications Commission (FCC) recently warned that the calls asking, “Can you hear me?” or “Do you pay most of the bills in your home?” are probably trying to record you saying “Yes” to use your own voice against you in authorizing charges on a bill or a stolen credit card.

“The problem is, the technology making these robocalls is cheap and easy to make, so it’s a low barrier to entry,” Susan Grant, the director of consumer protection and privacy at the Consumer Federation of America, told Moneyish. “They obviously work often enough that more scammers keep entering the market. And it’s hard for law enforcement to go after every single robocall, because there are so many of them.”

Last year the FCC created a Robocall Strike Force to hang up the con artists. The team revealed last month that they’re trying to develop technology to pinpoint where these calls are coming from so that they can shut them down.

“What people can do right now is use the tools that are being made available to them, and be very careful not to give personal information – like your name, Social Security number or birth date – to somebody who calls them out of the blue, whether it’s a live call or not,” said Grant.

And here’s what else you can do to protect yourself in the meantime.

  1. REGISTER YOUR NUMBER: Register with the free National Do Not Call Registry if you haven’t already at donotcall.gov or 1-888-382-1222. This will stop the legit marketers from calling you within a month.
  2. DON’T PICK UP: When you get an unsolicited call from a number you don’t recognize, let it go to voicemail. Many spammers won’t leave a message. “I hate to say you that you can’t trust any callers these days, but you certainly have to be careful,” said Grant.
  3. NEVER SAY ‘YES’: If you do answer the suspicious call, or respond to a voice message from an unsolicited caller, do not answer “yes” or offer any personal information during the conversation. If the caller asks something like, “Are you the homeowner?” or “Can you hear me?” politely respond, “Where are you calling from, and why do you need this information?” The sooner you hang up after sensing a call is sketchy, there’s less of a chance you’ll let something slip.
  4. THE IRS, SOCIAL SECURITY AND THE DMV AREN’T CALLING YOU: Hang up if the caller claims to be from the IRS, Social Security, the DMV or a similar agency, as government officials will only ever reach out to you through the mail, unless you call them first. And many spam callers claim to be debt collectors for debit and credit cards, student loan offices, banks and retailers. Hang up and contact your bank, credit card company or loan office directly to see if they actually need something.
  5. CHECK FOR CHARGES: If you fear you’ve let something slip to a scammer, check your banking, credit card, phone and cable statements for unfamiliar charges. Call the billing company and dispute anything that you didn’t knowingly authorize. Demand proof if they claim you were recorded approving the charge. And you can also contact the Federal Trade Commission to dispute charges.
  6. SEE WHAT YOUR PROVIDER PROVIDES: Look  into what spam and robocall controls your phone carrier provides to block unwanted and anonymous calls, like AT&T’s Call Protect, or T-Mobile’s Scam ID and Scam Block. “Most of these are free, so check your phone company’s website to see what’s available,” said Grant.
  7. THERE’S AN APP FOR THAT: Robocall-blocking apps are also popping up. Hiya, free for iOS and Android, flags potential scam calls, adds context to where unknown numbers might be to coming from and lets you report scam numbers in the app. Nomorobo for $1.99 a month on iOS works similarly to Hiya. Truecaller is a free iOS and Android app that alerts you to fraudulent calls before you pick up. And the free Should I Answer? app for Android crowdsources nuisance numbers, so users can warn each other about the worst unwanted call offenders.