It's Charter ....There have been a few people that have the same problem as you and this exceptable use policy will explain what they exactly do....
http://www.charter.com/Visitors/Policies.aspx?Policy=6
This is another interesting article....
http://www.complaints.com/directory/2004/june/30/9.htm
Try doing this speed test and see what speeds you get....
http://www.speedtest.net/
You can also try changing your listening port number to something between 49152 up to 65535, try this one 64049....