Robotic voice telling me "IRS has filed a lawsuit against you", blah blah, blah. The IRS does not call people to demand money, they send letters telling you that they believe there is an error in your taxes. They do not demand payment without allowing you to defend your tax paperwork first. They also do not stipulate how you must pay any owed taxes and penalties, and do not demand the payment be made by sending them a pre-paid debit card or by wiring money to a Western Union office. Total scam.
Just tried calling them back from a landline just for fun and to tell them off. The number is not a working number now. They must do this briefly and then move on to another number because I got the same message twice yesterday from another number.