Spam Control Considered Harmful

Art Houle writes...

So what do we do about this enterprising businessperson?

Same as any other. Make his efforts useless. Block the impact of it on
your own network. I still believe in blocking spam where it has the
impacts. Make mail relays un-hijackable. Make mail servers block the
spam for your customers (unless the customers wants it through in which
case they can configure or ask for that).

In this case report them to Prodigy.