Its a collection agency called ERG. They are rude and persistent. They called regarding a payday loan collection from over 10 years ago that I don't remember. They kept calling all day. I'm still mad. They kept hanging up on me over and over again. I read that if I send a cease and desist letter they have to stop calling,  but I have to find an address first. They are fraudulent and refused to send verification in the mail.

If you KNOW you owe no money, or believe the call was from a fake debt collector, please take the time to read this:
http://www.consumer.ftc.gov/articles/0258-fake-debt-collectors

Also, consider blocking their phone number ... google "phone blocker"

I've recently been harassed by a very rude woman who insist I owe a grand on a loan I Co signed for in 2005. She called today to ask if I have a lawyer to be served and since I didn't she said I would be served at my employers place of work.  She says she is representing USA CHECK CASHING.
I'm contacting San Joaquin sheriff's dept today.