Huge scam. They tell you that you owe money and if you don't pay, they'll send you to jail. This guy also said that they would make sure I would lose my citizenship, which is an absolute laugh. Don't believe them. The law firm they claim to be with has stated online that they do not do what these scammers are claiming. Plus, they use a live.com email, which no self-respecting attorney's office would do.
NOTE: USA does not people in prison because of debts. You can be court ordered to pay someone and can go to jail because of contempt of court, but not prison.
There is a very easy way to get them to stop calling, plus annoy the hell out of the scammers. I pulled a play out of their own book. With my google voice number, I continually called them over and over and over again, then fwd back their email to them over 100 times. Finally got a response back "F*** off, B****". I've not heard a word from them since. Nothing but a scammer trying to prey on fear. So turn it back on them. They will leave you alone.
They are real...first I thought they r not and hung up then they sent some guys after 3-4 days and now I have the notice to be in the court plus they informed my employer...now I have to deal with this