I'm sorry this is happening to you. This is going to sound geeky, but Clark Howard talks about this stuff all the time. His website will have plenty of information on how to fight this and win:
www.clarkhoward.com .
By the way, I know the one thing he definitely always says is to deal with it with the company itself (Charter), do not deal with the collection agencies as they have a tendency to circumvent the law if you don't know your rights.