No response when I answered. I called back & computer transferred me to an operator.
First National Collection Bureau.

They call 3-4 times a week then stop for awhile ... never leave a message. As the result of all the above messages I know who it is. I don't have any debt.

This is a debt collector who is trying to collect outdated debts that are past the statute of limitations.  If you look at their reports on the BBB website you will see that they use bad business practices in order to attempt to collect the outdated debt  http://www.bbb.org/reno/business-reviews/coll ... arran-nv-103653

If you respond to them just tell them that the debt is past the statute of limitations and that they need to stop bothering you or that you can sue them for harassment.  Of course their recourse is to threaten you with litigation and giving you poor credit ratings....they can't do either.  They may even threaten you with jail....also can't be done.  They don't have a legal leg to stand on and therefore cannot legally collect on the debt.  If you paid this company they will in turn sell the debt to someone else and you will be harassed by yet another zombie debt collector.

Your best bet is to deny the debt or even tell them that they have the wrong number.  I found this website that is right on the money about how to deal with zombie debts aka debts that are past the statute of limitations...
http://www.wikihow.com/Deal-with-Zombie-Debt

Who did you hire to take them to court?  There are a couple of debt collectors I have some serious dirt on and would love to slam them with a lawsuit.

Another loser with nothing to do but make everyone else's life miserable with unwanted calls.  469-304-9862 should get a life