[ChrisH]

If your flight is scheduled to arrive now over 4 hours later than your original flight, you should be given the choice to rebook on another flight. I'm not sure about booking on other airlines, but they should do that as well.

I would write them a complaint and be cordial, but also state your facts. You have meetings and other important matters to attend to and the delay is going to disrupt those plans. The airlines usually have some "small print" which states flight and flight times are subject to change, etc., but they are supposed to accomodate you if your flight will arrive after a certain period of time of your original flight, in the case of a schedule change. (I want to say it is 4 hours - someone correct me if I'm wrong). I would also add to your complaint that you are planning to copy the DOT in on your complaint.