Same scenario. Called and left threatening message that I need to call them before legal action was taken. Just for grins, I called the number back. A heavily accented man answered the phone and claimed to be from the IRS. I asked him if he was from the Internal Revenue Service and he said yes. I told him I didn't believe him. He stated, "I'm not here to make you believe I'm from the IRS" and hung up.
I just got this call as well from 301-960-3061 saying you must call this number as this is the IRS, call immediately to avoid legal action from the IRS and it was automated not from a person but a machine.
Recording supposedly from the IRS stating it is important that I return the call to a number in the 301 area code. The number was repeated twice. Since I had no way to write it down, I don't recall it. The call ended with a cheery "goodbye.." I agree it must be a hoax to elicit people to divulge their private info or send money. I plan to file a police report.