There is no "federal arrest warrant" for not repaying a loan, real or otherwise.  It sounds like you filled out an online application and gave them all your information.  Online loan places are run by criminals looking to get info so that they can con and scare people into paying extortion money.  Replying to their e mails was also not a wise choice.

Read up on your rights here, get template letters to send and also make a complaint at this government site: http://www.consumerfinance.gov/

Also file a complaint with your State Attorney General's office.
List of State AG’s offices:  http://consumerfraudreporting.org/stateattorneygenerallist.php

Caller said they have a federal warrent for my arrest and the case is in federal court. And I will be arrested unless I agree to pay them $975.00 for a loan.  At first I was scared that I would be going to jail for something I did not do.  But after reading these posts I realized I was being scammed.

If they call back and you answer the phone (I would recommend against answering) demand they send you a debt validation letter by US Mail. Emails, faxes, and phone calls are not legal methods of debt notification. If they were a real debt collector and not a scammer, they would do this.
By the way, you would never be notified in advance of a warrant, the police would just show up. If you're notified, you can hide and that defeats the purpose. And you cannot pay your way out of a warrant.

Caller said they have a federal warrent for my arrest and the case is in federal court. And I will be arrested unless I agree to pay them $890

Who sends emails from federal courts on Saturdays.  I wording of the email was certainly not good sounds like they are writing how they talk.  Who gets an email with a warrant for your arrest on it.  And garnishing my wages how are you going to do that.  It is a scam clear and simple.  I wouldn't reply to the email.  Lastly each time they write or call you owe more money to more places.