Complaint Review: sandpoint capital llc

According to this company i received a payday loan (unknown amount) over a year ago. To my surprise today I got a call from a woman stating there has been a lawsuit filed against me! Having never received a call,email or a letter I found this strange. She informed me that another woman was on her way to my job to serve me legal papers. I asked for an explanation- she told me nothing other than if I did not pay this immediately (today) that I would have to go to court and face jail time! How could this be legal? It feels like harassment-forcing payment without explanation. Needless to say I gave my credit card info so they could take payment for something I have no recollection of. I feel mugged! Is this legal? What can I do to get back the funds? Can I sue them? I feel that take their scare tactic to far, and it is truly scary stuff! I feel prayed on- not knowing my rights. Can anyone help????