It is doubtful your caller reads this website as it has nothing to do with them other than being a site to report who unknown callers may be. It sounds like a debt collector doing skip tracing trying to find the person whose debt has gone to collections. You can try telling them they have a wrong number but that only rarely works. If you can ever get a real company name and address from them you can mail them a cease and desist letter via Certified Mail then sue if they continue to call.