Others reported IRS  threat.  I tried calling number back,  no answer.  Caller ID: "wireless caller"

Calling #: 818 395-5704; Caller ID: "Wireless Caller"; Call @ 9:38 am ET, Tue, 16Aug'16:
Recorded message, female voice:
"Hello. This call is officially a Final Notice from IRS. Internal Revenue Service. The reason of this call is to inform you that IRS is filing law suit against you. To get more information about this case file, please call immediately on our department number: 818 395-5704. I repeat: 818 395-5704. Thank you"

Same as other callers...."IRS...."

Same message  as above I received tried calling back won't go through

The IRS would not call, you would get a letter.