Correct. When a “delinquent” debt is created by slipshod billing practices (say $40 billed to a closed credit card account) and then there is no good faith effort to re-bill, or contact the debtor, the “debt” can be demonstrated to be invalid. It would be written off and should disappear from the books. Grotesque interest and fees on such a “debt” are also invalid, if it can be demonstrated that the dunning process was flawed, negligent, etc.
For $600 you can purchase 2 hours of a lawyer’s time in order to get this done. A good one will disabuse a collections agency of the notion that they’re entitled to an 8-9X payment on a “debt” created by clerical errors.
There are legal protocols in every state that constrain collection of fee-inflated small debts like the one discussed above. It is painful to concern trollies to find out about them, but they exist.