A private investagator named calvin stated to my girlfriend that she owes on a payday loan what she does not know about but he had all her information, stating to her that she needs to pay or else she will serve time cause its a felony.

This is a scam number anyone getting a call from this number asking for money DONT give any credit card or bank account information.
DO Not give these people any type of information.

what did she do? I go the same phone call

You DO NOT owe them money. They are getting your information from a previous payday loan you may of had or from the information you submitted online for the loan. They will have your SS #, yoru adress, you home phone, your employer and anyone that you listed as a refernece. DO NOT PAY THEM! They are scam artists and you CAN NOT be arrested for an unpaid debt. I urge everyone to NOT give these people anything. Demand they MAIL you the original debt, the orignal owner of said debt and their company's name and address. Also remind them it is a FEDERAL CRIME to impresonate a law inforcement officer or a private detective. Let them know you will be contacting the Attorney General along with your attoney. Warn anyone you may of put down as references about this scam, as they will also contact them!

This number 904-527-3258 comes from Jacksonville Florida
Did a search on this number it comes up with names as
Lonnie Burton
Mary Burton
Richard Burton

Address:  4211 Moncrief Road in the Jacksonville FL area
If you do get a call from someone from this number I would call
your local police ,or the Jacksonville police the Attorney General

Yes they are SCAMMERS and they want you to send them money by a certain time
or you'll be arrested this is all bogus.
DO NOT send them any money by Western Union.

If they call you again tell who ever is the PRANKSTER is to send you a letter in your mail in Black and White so you can have proof.

They will keep calling you sometimes 1 or 2 times a week and make threats demanding you for a certain amount of cash DO NOT FALL FOR THIS Call Report it Right Away.