I forget exactly what I did, but it was an FCC complaint. Here's what one of Comcast's executive customer relations officers sent me after the FCC complaint was processed (with parts removed):

I am writing in response to the FCC file received in our office on December 2, 2014 regarding your request for the disconnection of your Comcast Business Service. I apologize for the inconvenience and frustration this has caused.

I have forwarded your concerns to the Business Services Group and you should be contacted by a representative concerning this issue. If you have any further questions, please contact me at ----------, ext. ------- and I will be happy to forward any questions or concerns you have to the correct group. Thank you for your time.