Within 5 days they are required to send you a letter, notifying you that you have the right to dispute the debt. If you do not have their address yet, that will get it for you. Send them a letter certified mail, telling them that you dispute the debt, and you want to know when the last payment was made.

Since your last payment was made 6/28/05, the SOL has expired. As soon as they send you this, send them another letter, telling them you are not going to pay, and not to contact you again. That should do it.