The first thing you want to do is a little research to find out if they really have an outstanding judgment. Per the FDCPA if you write to them requesting a copy of the judgment they are required to supply you with a copy. If they don't send you one (because they lied) then you can sue them for an FDCPA violation in misrepresenting the legal status of the debt. You'll get an easy couple thousand in a settlement from them for a small investment of a filing fee (or many attorneys will file the suit for you at no up front cost...the FDCPA required the agency to pay your "reasonable attorney fees" if the are in violation).
If they do however send you a copy of a judgment, that changes things as in many states they have 10-20 years to execute on a judgment and can renew the judgment as well. In that case, you may want to explore settling with them...depending on where you live there could be any number of remedies available to them in executing on a judgement....and a cease and desist letter does not require them to cease execyon a judgment, only to cease communication with you with the exception of legal process. Given the age of the alleged judgment I would imagine you could negotiate a settlement for a very small percentage (maybe 20-30%) if you can sell the idea that you're in reduced circumstances which aren't likely to change and better they take that than get nothing at all.
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