My name is XXXXX XXXXX I'd be happy to answer your questions today. I'm sorry to hear that this happened.
The starting point is to look up the judge and find out what court he works in. From there, he should be able to call the clerk of the court and get a copy of all documents filed in the case. If he doesn't have the case number (which should be on the writ), he can ask if they can look it up by name. Not all courthouses will mail documents, and it's faster to go in and get the records, but he should call first to make sure they have it.
Once he finds out when the case was filed and where, if he was never served of notice of the suit, he can file a Motion to Vacate Default Judgment, explaining that he never knew about the debt. The statute of limitations
for breach of contract
in Washington is only six years, so if this really is a debt that he incurred 13 years ago, he should be able to have the default removed. Then, he'll be able to ask the judge to dismiss the case based on the fact that the statute of limitations has expired. What matters isn't when the collection agency bought the debt (they shouldn't be buying and trying to collect expired debts under the Fair Debt Collection Practices Act), but when he last made a payment or borrowed the money, whichever is later.
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