Think about it: that post (and the comments by robyn_b below, an account which was registered 20 minutes ago) goes out of its way to SEO-ify for keywords related to the founder, his company's name, and related variables.
This is the risk you run with every single customer service interaction -- that the guy on the other side won't just be content to take his ball and go home if you can't meet his demands, but will try to foment a mass movement against you to put you out of business.
Good service is unfortunately not a panacea for this problem. Suppose that 99.9% of your customers are satisfied, but you have millions. Then you've got thousands of disgruntled people out there, and bad news travels fastest.
The lesson, ultimately, is that you simply can't respond in a human way to someone attacking your baby. You need call centers and roboscripts and a first layer of customer service, such that if a customer decides to attack you on the internet, a manager can jump in, offer concessions, and make it all better.
Doing it any other way means that you run the risk of a candid response becoming a capital crime.