I filled for chapter 7 in 2006. I did not put this person down as a collector which was in the amount of $15,000. Is there anything I can do? This person now is coming after me trying to collect..

If there were no assets for distribution in your case, no deadline would have been set for filing a proof of claim.  If that is the case, the debt was included in your discharge.  Provide a copy of the discharge to the collector, and if they keep it up, they will be violating, among other things, the Fair Debt Collection Practices Act.