My question involves collection proceedings in the State of: NY

In January of '08 a default judgment was made against me; my bank account was frozen. Shortly thereafter, I filed a motion to show cause (I was improperly served...letter sent to wrong address), and the original judgment was ultimately vacated. It is now Aug '09 and I am being contacted by a different third party agency. I do not agree to any amount owed to the original creditor, but finding proof to support that would be very difficult. The original creditor was Credit Card Company, the account has been charged-off, sold, and the account was last reported delinquent in 2002. Can this new agency take any legal action against me?
FYI- The new collection agency said they sent a validation letter on June 30th of this year to the WRONG address again! When I was contacted by the rep last week I asked that he send me something in writing. It was not the validation of debt, but it did have pertinent information; original account number, their account number, the old index number for the vacated judgment case. (he also mentioned that there was a judgment against me when I spoke to him, I told him it was vacated and he asked that I send proof. That request was made yesterday and I haven't done so yet because I'm unsure if it's prudent to do so).