I finally got them to cancel the internet they fraudulently signed me up for. Here's the kicker:
They tried to talk me into staying with them by offering me... a month of free internet!
What makes a company think that the best response to someone who has had enough of pathetic service, roundabout customer support and a thoroughly unsatisfying experience is to attempt to bribe them back by offering them the exact same product they've spent the last month trying to avoid? How about comping me the six hours I've spent on the telephone talking to "customer service agents" who are apparently told that "customer service" means "sell bundles like they're made of cocaine"? Gah.