if you can show that the collection agency violated the Fair Credit Reporting Act, the Fair Debt Collection Practices Act, or potentially LA State law. you can sue them for the methods they've used to collect the alleged debt. i.e.: If within 30 days after this collection agency first contacted you, you requested (preferably in writing) that they "validate" this debt by proving that it's yours and how they came to the amount owed, they must cease all collection activity until they provide said documentation. this includes listing it on your credit report, calling you for money or sending any more letters demanding payment.