I got calls from this number but never a message.

The IRS is filing lawsuits against you scam.

"internal revenue services" supposedly filing a lawsuit unless you call back.

You should know that the IRS sends notifications via postal email.

IRS Scam call message, same as above message.

Same.  The message says "Internal Revenue ServiceS" (plural) and that they are "filing lawsuit against you."  Bad English.  I guess none of us have called the number back!!!  Jerks.  Although it took a minute to figure out it was bogus, that minute was kinda scary.