"Service" agents aren't very helpful

After changing the time of a flight FIVE times and making passengers sit in a plane for 30 minutes, the service agents have the audacity to become snippy when passengers ask what's happening. On contacting customer services to get some help, there are no answers. When a service agent with some power to help is finally found, he makes promises he can't keep. The worst is having a service agent refusing to give her name (Susie Chung, Ronald Reagan Airport, DC) when you make it clear that you are going to complain about her lack of service. Remember, United is in business because of flying customers...