Debt Validation Letters: How to Use Them to Crush Debt Collection -

Your first line of defense against erroneous debt collectors is a debt verification letter. It is frequently—but not always—a mistake not to use it. If you don’t send one, a debt collector may presume the debt is still valid and pursue collection. 

A debt verification letter can swiftly cause a debt collector to back off if the debt is not legally real and the debt collector has little or no possibility of ever forcing you to pay.