They call, they email and they mail. They sound official on the phone, or their "notices" look official on paper. It has been a really hot summer for scam artists posing as federal agents or the Internal Revenue Service, trying to get unwary consumers to send them money by intimidating and threatening them.

Denys Prykhodov, ThinkStock

So far this summer, the scam the IRS has seen the largest increase in is by phone, where the scammer calls someone pretending to be an IRS employee. The caller will give their name, a badge number, and will start by threatening with either arrest, deportation, or a lawsuit.

But IRS spokeswoman Anny Pachner says the revenue service does not call and threaten, or even send something that threatens arrest or deportation.

"That is not the IRS calling," she said. "What we are doing is just letting the public know, if you receive a threatening call from someone pretending to be from the IRS, just know that that is not the IRS calling."

Also, Pachner said scammers who demand payment without appeal or due process are just trying to take advantage of you.

"If you are required to make immediate payment over the phone or through a wire transfer, it is also not the IRS calling," she said.

Pachner said the first legitimate method of contact from the IRS is by mail.

"So, we will first send you a letter letting you know that you owe taxes to the IRS, and we will actually give you the opportunity to question or appeal the amount that you owe," she said. "We will not call you threatening arrest or any kind of law activity."

Because the IRS is really getting the word about these phone scams, the scammers are now coming up with new ideas. They recognize that people are starting to become aware of phony phone calls, so they have begun instead sending letters or notices. These notices say that the targeted victim either has to contact them to pay taxes owed, or will ask the recipient to confirm and verify personal information -- which they will then use to commit other crimes.

"What you should do, if you receive a phone call pretending to be from the IRS, or if you receive a letter, a notice, a bill pretending to be from the IRS, you should really take a careful look at that letter," Pachner said. "The letters that we are seeing that are going out to taxpayers are very similar to the forms and the notices that the IRS sends out. They will have some minor changes to the IRS website. Instead of '.gov,' they will say '.com.' But it is very hard for the average taxpayer to figure out whether or not it is from the IRS."

Pachner said the authenticity of these notices can always be verified simply by calling the IRS hotline: 800-829-1040.

"You should first contact the IRS to make sure that it is actually us trying to reach you," Pachner said.