Go public. If you've had a terrible experience and aren't getting the desired response from the company, consider complaining publicly, through blogs or the media. Says Emily Yellin, author of Your Call Is (not that) Important to Us: Customer Service and What It Reveals About Our World and Our Lives, "Different companies pay more attention to [what's being said about them on] the Internet. Getsatisfaction.com is a great site, founded in Silicon Valley. Their whole thing is creating a social network to bring companies and customers together in a community that's civil. You have to use your full name and there's a real conversation [between customers and companies]."
Despite their sometimes impenetrable automated phone lines, companies are not the omniscient, technologically advanced entities they often present themselves to be—and it's up to customers to hold them accountable.