This number called me claiming to be the irs filing a lawsuit?

Received several from this #   First time,only,included last four digits  demanding i call them. After a few more times of Demands but no full phone number one day last Saturday she said the IRS your last chance before we sue you something like that and gave all 10 numbers I don't think it was not a recorded voice but one of those mechanical voices used with phone trees given a demanding/threatening tone.it