Client: You can't charge me for cancelling that meeting; you didn't respond to my email requesting confirmation.
Me: For one, I confirmed the day before, as we normally do. For another, you sent that email four hours before our meeting, which is 2am my time, and then canceled two hours after that.
Client: I sent that email at noon my time, which is a perfectly reasonable time to expect a reply. I work with people all over the world and cannot be expected to keep track of YOUR time zone. It is not my problem that you were not available to respond timely.