Here is AGN Network's contact info. They are a provider for a computer system that does automatic calling for sales/telemarketing companies, so it's not actually AGN that calls you, but they can remove you phone number from the database. They seemed very friendly when I called the SUPPORT number, and other calls were coming in so it should stop.
sales:
[email protected]
support:
[email protected]
billing:
[email protected]
sales: 888.811.VOIP (8647)
support: 877.627.2686