When a company realizes that their chances are slim to none on collecting a debt that is owed, they do what is known as a
charge-off.
This is an accounting term meaning the company wrote the debt off as a loss, it does not mean you do not still owe the money.
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I have no idea what you should write in response to the lawyer.
Maybe someone else can give you an idea on that.
You don't deny that the debts belong to the two of you and the statute of limitations in Michigan is 6 years, so I don't know.