The caller says he’s from the IRS and that you owe taxes – pay up or cops will be at your door in a few minutes. Or an email from the IRS pops up asking for your Social Security number or bank account information to clear up just a tiny confusion about your return from a past year.

Don’t buy it. And don’t get scared and rattle off your personal financial information.

IRS imposter scams skyrocketed recently, according to the Federal Trade Commission: there were almost 55,000 complaints in the last tax season, up twentyfold from just the year before. Scammers typically claim to represent the IRS or Treasury Department – often complete with a phony badge number, altered caller ID and realistic websites – and try to convince you that you owe the government money, need to fix a past tax problem or are due some kind of bonus refund.

These crooks may know your name, the names of your family members and a portion of your Social Security number or other information (which they’ve usually obtained using Internet data-stealing, aka phishing, cons). Sometimes argumentative and insulting, they may leave a message that requests an urgent callback.

Favorite scammer targets are also those most likely to succumb to the trickery and least able to afford the theft, such as older adults, immigrants and widows or widowers, according to advisor Sheri Iannetta Cupo of SageBroadview Financial Planning in Morristown, N.J., and Farmington, Conn.

The call coming out of the blue only increases chances of a rip-off, says the IRS. On its consumer alert webpage the agency maintains that it never calls to demand immediate payment or about taxes owed without first sending a bill. Sure, if you defraud the government it’s possible to incur fines, penalties and even jail time, says Cupo, “but none of these events happens in a vacuum.”

The IRS sends letters by postal mail and doesn’t initiate contact with taxpayers via email, text or social media, nor does it ask for information about your debit or credit cards over the phone.

“Many times the people contacted have lived in the same location for many, many years, so the idea of [the IRS] mail being lost is very low,” adds Jim Blankenship of Blankenship Financial Planning in New Berlin, Ill., who is an enrolled agent. “The IRS would never, upon first contact, ask you for immediate payment or threaten that the police will be at your door.”

“Scammers demand payment immediately and threaten jail time for non-payment," says advisor Kimberly Howard of KJH Financial Services in Needham, Mass. "They demand you wire the money or, worse, demand your credit or debit card number. A big red flag is that they’re unwilling to review your tax situation or explain where and why you have overdue taxes. The most important clue is that they make demands without an explanation.”

Hang up, Cupo advises, just as you wouldn’t politely converse with a burglar in your home or a mugger on the street. You can report the call to the IRS, noting the caller’s number. “You can also always say you will return the call when you have your tax returns in front of you,” adds Howard. Never use any phone numbers the scammers provide.

Online scams tend to involve fake emails or websites. The IRS says that criminals may pose as a person or organization you trust or recognize – a bank credit card company, tax software provider or government agency – and sometimes email under another person’s name after hacking into an account. Crooks’ websites can appear legitimate but contain phony log-in pages to snare your money, passwords and other information – not to mention infect your computer with malware to mine your data.

In one recent example cited by authorities, scammers invite you to a mirror version of the IRS site and direct you to “update your IRS e-file immediately.” The emails mention USA.gov and IRSgov, though not IRS.gov, the government agency’s real site.

Report online tax scams to phishing@irs.gov. Open no attachments and click no links in any email or message that you suspect.

Scams continue to evolve. Burbank, Calif.-based CPA Brian Stoner confirms that a new online con targets professional tax preparers themselves. “I’ve gotten 10 to 15 emails from ‘new clients’ wanting taxes done where I had to click a link to access a previous tax return or current W-2 on some portal,” Stoner says. “If you click that link, there is some phishing software waiting to get your taxpayer info, maybe passwords and other items to possibly get access to client information.”

Scams continue to reach “ridiculous lengths, to the point you wonder how anyone hasn’t been targeted,” Stoner says. Last year tax crooks even called the home of the commissioner of the Connecticut Department of Revenue Services.

“Just don’t panic,” Stoner says, “and check it out.”