Mcm Manhattan Harassing me and my family emailed me that I was going to jail. I've reported to fbi Internet

I want you to know that I am not an attorney, or law enforcement.  I am just an average person that been in a similar situation.

Please do not take my educated comments as being total fact.  You need to investigate.  I want to point you in the right direction. 

First off,  its my understanding that threatening you with jail is not right.  Reporting it to the FBI is the first step.  I would suggest that you Report this to Consumer Financial Protection Bureau.  I would also report this to your State Attorney General and the Federal Trade Commission. 

The Consumer Financial Protection Bureau is apart of the Federal Government.  I suggest you provide a copy of the email and what they told your relatives on the phone.  

I would also check into recording those calls.  Research the number it came from.  There is a lot scammers calling and claiming people owe money.  These people are foreign speaking and from overseas.  Do not give them card or bank information.  you need to check whether your state is one party or two party state.  Research that and if it will work.  Then record them. 

Now another suggestion is to contact a NACA attorney.  I had one in 2014.  He did a great job for me.  Research anyone you consider to retain.  Now,  You need to find out whether those doc you are getting are authentic.  I would look at the documents and try to determine what county or state court it mentions.  I would call and find out whether a case has been filed against you.  In fact I would visit the clerk of courts. I would check maybe online every two weeks or so.  Be proactive.  There something known as sewer service.  This where they commit all sorts of fraud.  So you do not appear in court.  Because you were not aware of a complaint pending.   By not appearing.  The court will award  them a default judgment.   Then they can seize property, garnish your paycheck etc.

Its better to be proactive then reactive.  I wish you the best of luck. I hope it works out for you.  Remember,  do not shrug this off.  Be proactive.  Do not be scared,  There is help out there.  File those complaints.