It's a collection agency.  Just hang up on them.  They can't and won't do anything to you except hit your credit report.  Don't let their scare tactics get to you.  Nobody is taking you to court.

They called didn't leave a message.I have checked the number out.its a collection agency for Navient who supposedly brought out Sallie Mae student loans. They will call You from alll kinds of numbers from robot number,spoofing your number for the person you really want to see if you will and if the person is friends,family,or their associate,they probably put you down as emergency contract or cosigner. They also call from Delaware ,Virginia, California, 1-504-838-0111, and a host of other phone number s. The message may say this calls on hold, sometimes nothing at all just holding the phone,sometimes background noises,ect. They start calling as early as 8:00 am mountain standard time. They will still call You even if the borrower is paying them. They are scamartist. They have claims against them. Don't reply if you know you don't owe them anything or every done businesses with them. You can send them a Stop Harassment letter. Look up online for your state rules.

Don't let the [***] scare you.  Never send a single penny to any collection agency.  Always ask for a copy of the bill they are trying to collect to see how old it is.  If it is still within the legal statute of limitations, ask a lawyer to settle.  They buy your debt for pennies on the dollar.
They will take .15 to .30 cents on the dollar but you need to make sure it is in writing and payment in full.   Do not send them a dime until you have enough to write a check for the 15% settlement.  Monthly payments to a collection agency are a waste.  Never send them a dime.  All they can do is sue you.  Even if they do sue you, the lawyers will take the same reduced settlement amounts.  It is not worth their time to chase you on the judgment.