While my experience wasn't with iUniverse, several years (I'm thinking five or six at this point) ago I heard of a service called XLibris. XLibris is basically a vanity publisher and, unsurprisingly, on Predators & Editors watch list. At the time I was ignorant of P&E and vanity presses and asked them for information.

What I got was a packet of information explaining their services and then I had an "account agent" calling me once a week for a month two weeks later about "my manuscript". It didn't matter that I didn't have anything completed or that I was just trying to find out information, I was basically hounded about the writing I was doing and it creeped me out. I told the woman that I found the behavior unprofessional and to take me off her list.

Last year or 2007 I got a call from some new guy at XLibris asking about my manuscript. I asked him how he got my number and he said it was in the system; I informed him that years ago I'd asked them to take me out of the system as I had no real wish to do business with them. He got snooty with me and that's the last I've heard from them.

I'd just make a filter that automatically trash their e-mails and complain the next time they talk to you to a supervisor.