<prompt> Human: Hi - whats the next step when a collection agency will not send a debt validation letterdocumentation by mail? A collection agency has called about half a dozen times, and each time I have asked them to mail me documentation proving that they own this debt and information on the debt. They have refused, sometimes aggressively. I would be willing to pay a debt that was legitimate, but its not clear that this agency is. What is the next step from here? Should I be sending letters to the credit bureaus? What is the downside of ignoring these calls moving forward?  <response>: This page from the Consumer Financial Protection Bureau may help you figure out your next steps: 