If the statute of limitations on paying this debt had expired there may not be an avenue to use the courts in the modification of divorce decree process. This is a very detailed fact situation so check with a lawyer in your locale to discuss more of the details.
You might find my Legal Guide helpful "Ethics: Yes I Need a Lawyer!"
You might find my Legal Guide helpful "How to Choose A Lawyer For You."
You might read my Legal Guide "Can An Attorney Really Help?"
Good luck to you.
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