Curious if this a legit message or not

Adveertised a free husky but wanted $300for shipping turns out to be a scam kept calling for hours.

I ALMOST FELL FOR IT HE HAS BEEN HARASSING ME FOR DAYS !!! MY COUSIN GOOGLED THE COMPANY AND NUMBER !! THANK GOD SHE DID !!!!

TOLD ME HE HAD A ENGLISH BULLDOG FOR FREE BUT $300 FOR SHIPPING !!!

Posed as IRS.then tried to extort 4000 $ called me a [***] after I called his bluff

Recorded call said the IRS is going to file a lawsuit against me.