Now is the time to speak up !
Comcast has been documented to be illegally blocking international e-mail to it's individual and Biz subscribers in the U.S. so this deal with getting a subscriber fired over Comcast's failure to correct over-billing errors does not surprise me at all. I have had friends report outrageous experiences with Comcast e-mail support that is out sourced to various Asian countries where they can't even speak the English language.
Comcast already has a semi industry monopoly as proven by their illegal operating practices that are not being terminated by U.S. Federal authorities even when reported by Comcast subscribers. Now Comcast wants to merge with Time Warner Communications so they have a complete U.S. industry monopoly. This is BAD for all concerned except Comcast and can not be allowed under ANY conditions.
If you are a U.S. resident or if you routinely communicate with individuals or Biz in the U.S. via e-mail or phone, you had better make your views known NOW or forever suffer the consequences of the unscrupulous actions of Comcast.
http://transition.fcc.gov/Daily_Releases/Daily_Business/2014/db1001/DA-14-1431A1.pdf
You can also file an anti-trust violation with the U.S. Federal Trade Commission or a complaint or both and I suggest that everyone who cares do so.
http://www.ftc.gov/faq/competition/report-antitrust-violation
https://www.ftccomplaintassistant.gov/GettingStarted?NextQID=251&Url=%23%26panel1-8#crnt