If a debt collector contacts you regarding an old debt, do not admit that you owe the debt and do not agree to make any payments. Simply tell them that the "statute of limitations has run on this debt and do not contact me again". If they continue contacting you, send them a certified letter, return receipt requested, telling them not to contact you about the debt again. Remember -- DO NOT ADMIT THAT YOU OWE THE DEBT, DO NOT AGREE TO PAY THE DEBT, AND DO NOT AGREE TO SEND ANY MONEY TO THEM. If you do, then the statute of limitations might start running all over again, giving them the legal right to sue you. May depend on the state. This is the law in California.
State Statutes of Limitation on Debt Collection