I know it sounds kinda pointless, but perhaps you could see about complaining to a government consumer protection agency? I don't think the FTC (federal level) would be ideal, but they MIGHT be able to help, seeing as Comcast is located outside of IL. This type of customer neglect might qualify as breach of contract, or at the most "unfair" business practice (as Comcast has a monopoly on cable internet in most areas). Either that, or you can at least threaten such on the phone to get someone to fix your damn internet.

Seriously, though - can you look into an alternative internet provider?

--Jeff