As of Feb 1 this year....
First, the server IP addresses, to be used for traces/ping plots.
Axis vs Allies, Late, Special Events 1, The Playroom, Custom Arenas: 71.252.137.154
Dueling, Training, Early, Mid, Special Events 2, World War I: 71.252.137.153
However with AH3 just released it may have changed.
HTC is not responsible for the internet. Their request to an ISP are pretty much handle the same way your request to ISPs would be handled. You can contact your internet provider and tell them about the issues but it may be difficult to get them to act. The more you push the ISP the farther up the chain you will get and the better the response.