RCN just jacked our bill up, too, and I called them and negotiated it back down. We're now paying $109 a month for basically every cable channel except HBO (including HD and all other premium channels), telephone service, and a 20mbps cable modem. We had to agree to a two year commitment to get that rate but that was fine with me because that's basically 2 years in which I don't have to call them every 6 months and negotiate our rate.

Call them and threaten to quit. Tell them Comcast has a better deal. You can get your rate back down.