You are right, you would be either mailed something that you would have to sign for or it would be delivered in person by someone who is legally allowed to deliver it.
Man called said I was going to have legal action against me for an emergency room bill from Arkansas. I've never lived in Arkansas he got mad said he would report it to credit bureau and slammed the phone down
I got a message from this number stating that they had a pending case against my mom with her SSN on their desk. No name, no agency and no reason was given.
I did some research and it looks like it is not legitimate!