I couldn't disagree more. Granted my search marketing efforts on adcenter are the least aggressive of the top 3 engines where I run campaigns, but my dealings with their staff have always been very positive. In my experience when calling Yahoo Search Marketing, there is a very simple equation:
The number of different answers to a question or stories you receive from their staff is always greater than or equal to the number of times you pick up the phone. This number will go up if you are transferred from one rep to another during a call.