Scammers use fake 'bad debt' to terrorize you using a bad debt scam to trick you.
Whether this is true or not, do not give them any personal information. Do not confirm or deny anything. Do not give them any payment information. Hang up.
They may even give you a number to call claiming they have been trying to serve you and you need to call the server processor. FAKE! They will claim your home will be taken away from you, or your wages garnished. They will say an officer will be on the way with an arrest warrant if you do not agree to settle your 'fake' bad debt right now over the phone.
DON'T DO IT! IT'S FAKE!
The scammer has spent time researching you and will have information that sounds very convincing. Often they find something in your past up to 5 to 10 years ago from a car loan, home mortgage or credit card lien against you to convince you it's real and to stop the arrest from happening.
IT'S FAKE.
If they get a credit card payment from you, it will only be used to rack up charges on your card, or they will sell it on the dark web to the highest bidder. They will also sell any personal details as well to commit Identity Theft against you.
Hang up, then block the number.
Take note: They will call you again and again in hopes you respond, often leaving messages with a phone number to call.
Remember: This is not how our system works and any legal issues will always be through the postal mail first at your last known address, posted in a local news paper or through the local Sheriff's Department.