The deadline for filing your taxes was April 15, but tax scammers have no deadline.  In a quest for personal information and money even after filing deadlines, scammers often impersonate the Internal Revenue Service (IRS).  "The IRS encourages taxpayers to be vigilant year round against phone and email scams that use the IRS as a lure," the IRS said in a statement e-mailed to CNBC.com. "These scams won't likely end with the filing season so the IRS urges everyone to remain on guard," the IRS said in the email.  Can you trust caller ID?  Since October, the IRS has been warning Americans about a sophisticated phone scam that remains pervasive and frequently targets immigrants. The scam has cost the victims more than $1 million, and there have been roughly 20,000 reports of the scam, according to a Treasury Inspector General for Tax Administration press release.  The scam begins with a phone call claiming to be from the IRS. Usually the scammer will say either the call recipient is entitled to a big refund, or they owe money that must be paid immediately. If the recipient refuses to pay, the scamming caller often becomes hostile and threatens jail time or a revocation of the individual's drivers' license.  The phone scam is so sophisticated that the scammers are able to outsmart caller ID technology so that the IRS's number appears. Adding to the appearance of legitimacy, the scammers will offer fake IRS badge numbers and often know the last four digits of the victim's Social Security number.  When receiving one of these calls, "people have to step back and take a deep breath," said Laura Iwan, senior vice president of programs for the Center for Internet Security, a nonprofit that focuses on cybersecurity. She suggests targeted individuals immediately contact the IRS to see if the original call was legitimate.  Other signs the call may be from a scammer include the caller asking for payment using a pre-paid debit card or wire transfer, or asking for a credit card number. The IRS will not ask for this type of payment, nor will they ask for your credit card number over the phone.  Additionally, the IRS's primary correspondence method is through the U.S. Postal Service.  Read MoreFiling taxes online? How to protect yourself
If you’ve filed tax returns and think everything is OK, guess again. Phone and email scams try to nab your data by impersonating the IRS.