How to cancel Comcast service online

Oh wait, you can't actually do that.  You have to call them.  Comcast TV and Internet is generally quite excellent, but if you need to do something that relates to giving Comcast LESS money, or there's a problem with your service?  They fucking SUCK.

Here's what came up when I entered the query "cancel service" on their "support" page.  Spectacular support I'd say.  Exceeds server limit indeed.

Bad Request

Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.

Cookie

/n

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Apache/2.2.15 (CentOS) Server at sitesearch.comcast.com Port 80