Still calling every day but wont leave voicemails. From what others are saying, this is nothing but a scumbag scammer trying every story in the book to get people to part with their money. Even posing as a debt collector is part of what they do. Don't give them any money or information.
These jerks just called my elderly father and impersonated a federal marshall. They tried to scare him into sending them money, claiming he had ignored a summons to jury duty and would be thrown in jail. Crooks!
Contact your local courthouse and give them that information.
Many states exempt elderly people from jury duty.
Ask if your father can be exempted so his name is never drawn again; this will help him know that future calls making this allegation are lies.