Outstanding Loan/but was paid in full

My mother received a message from a Jason Hunt stating that her or my sister should call them back immediately or "it would not go well for them" my mother was concerned and returned the Call. They stated that I was under investigation the prime suspect in a criminal proceeding and they could not give her any more information or she could be in trouble as well.  They told her that I had to call them before 1:00 PM today.  I called them and they told me they were with the Crime Prevention department. They said I did not pay a loan with CASH NET USA for November of 2007.  I have a receipt for full repayment of this loan.  When I asked for more information They put me on hold and then the line was disconected. I called them back and asked them what it would take for this to go away and that is when they asked for  $633.00.  They wanted my credit card or debit card number. When I asked if I could mail them a Certified Check or send them money from western Union they said they only accept Credit Cards or debit cards.  What legitimate Company does not take Cash?  I have reported this to the FBI and Contacted my bank and the fraud department at Cashnet Usa.  However I want to let everyone know about this because it is pretty scary to be told that the police/Sherrif will be coming to your work or home to arrest you. Please report any information you have to your local FBI Office.  The phone # on your caller ID may be 815-359-8994