According to our sources the statute of limitations for most consumer debts in Virginia is five years. However, we don't have information that confirms that also applies to medical debts. In some states it is different.
I would recommend you check with the Virginia Atty. Gen.'s office or consult a consumer law attorney. If you confirm that the statute of limitations has expired on this debt then you can send the collector a cease and desist letter instructing them not to contact you again.