My girlfriend had this happen to her at Earhlink. You remember all their commercials about how they are 100 percent against spam, bla, bla, bla? Well, when she called them and explained what was happening (she was getting some NASTY mail from ppl that had been spammed), EL said that they could do nothing. They offered her a new address, which she took, but they forwarded her old e-mail to her new as one of the benifits of "moving" within their system!
So it basically solved nothing, she dropped them and went with someone else, and swore never to use them again.
Any way, the point of that was to say I know what you're going through.
Indy