Anibal Jose Baez
Over the phone, it has happened to me. I tell them "I am the Sole Authorized Administrator for ...", and they tell me they need to talk to the PERSON, or that they cannot continue the conversation. :D And then I tell them that the PERSON cannot speak, but that the Sole Authorized Administrator can speak. If they refuse to speak to the administrator, I inform them that then, they are choosing to communicate only in writing.