When you call the number back their mail box is full...can't get off their forking phone list. Next time find out who they are calling about and report THEM for using this service.
This is a scam I am tired of these people they call constantly they are desperate saying they are from the IRS. Do these people think we are stupid? You can tell them to get lost and they still call again and again almost always using a different phone number. There must be a way these people can be caught it is outrageous.