Before we dive into why or when it makes sense to pay, ALWAYS start by sending a debt validation letter. The best time to do so is when the collection agency sends you the first letter in the mail alerting you to the fact that a debt has been placed with their office. This is called a dunning letter.
According to the Fair Debt Collection Practices Act (FDCPA), you have the right to dispute the validity of the debt within 30 days of receiving the dunning letter. This is the best time to send the letter. Debt collectors are barred from collecting or reporting the debt on your credit report until they validate it as yours.
But, even if you didn’t respond to the initial dunning letter, it is perfectly fine to send the debt validation letter later. Most third-party collectors will remove the debt from your credit report if they are unable to validate it as yours.