After he left a review about it in Yelp, the online review site, he was rather surprised at the response he got from the Pizza Shop Owner Amy - (although it has now been removed due to the amount of interest from the media, you can still read the other posts).
Read the story here (Case Study A)
For what its worth, my opinion is that if you want to operate a business these days you have to appreciate the power of the customer to give feedback that is instantly available to the whole World, and you should learn to turn it to your advantage in the way that Chicago Domino's Pizza Franchisee Ramon deLeon did in 2009 (Case Study B)
Read how he turned a negative online review into such a positive outcome here (a Blogpost that has been linked to over 3,000 times!) and watch the famous video apology (seen over 15,000 times!)
I'll leave it up to you to decide the best way to respond to customer feedback
Oh, and just to show you how seriously I take Customer Service, we had the opportunity last year to ourselves "go the extra mile" and resolve a complaint using Social Media.