People about to receive arrest warrants are not warned or threatened in advance. They are not told that sending money will stop the warrant server.
If you were threatened with an "arrest warrant" via a phone call or email, read this:
"The warrant is phony. A valid warrant would not be served by fax or e-mail. It would be served in person by a U.S. Marshal or other law enforcement officer."
"Anyone receiving a fake arrest warrant should contact the FBI or the district U.S. Marshals Office. If there is any question regarding the authenticity of a warrant, contact your district clerk of court."
http://www.consumer.ftc.gov/articles/0149-debt-collection (Threatening civil proceedings with no intent to follow through, or threatening criminal process in order to collect a civil debt is a violation of the Federal Fair Debt Collection Practices Act.) The same goes for endless telephone harassment
Also contact your local attorney general
If they continue to bother you, and you know you do not owe any money, tell them that you know this is a debt scam and that you are making a complaint to the police for extortion. Once you get a copy of the police report and they call you again , just read out the file number and the name of the PD or Sheriff’s office involved. Tell them you’ll be glad to send a copy to them at whatever address the jack***es are working out of now.
You'll probably have to yell at them and talk over them.
You have to get tuff with these people because, being akin to thugs, brute force is (metaphorically speaking), the only thing they understand.