Example the First: How's that working for you, Cycles & More?
Example the Second: Does litigation make it better, T&J Towing?
Just a hint. No matter what you, as a business owner or employee may have gotten away with in the past, this is a whole new world. Offend a customer, and become a star of the blogworld, on Facebook, Twitter, Yelp, and more - a whole new level of negative fame.
Try litigating your opponent into silence, and watch your business implode, as the 'net community responds to what is perceived as an attack on freedom of speech.
Your business (and very possibly personal) history will be examined and published, every complainant you've ever had will suddenly be talking to each other (and comparing notes and attorneys while raising their united voices in publicly retelling their tales of woe regarding your business and the essential vileness of your business practices in their eyes).
This will not be good. The balance of power has shifted. The Better Business Bureau was...annoying...if you weren't a good business critter, but it was fairly toothless and most folks couldn't be bothered to check your business with them before *doing* business with you. Lifting a phone was too much effort.
A quick Google search, on the other hand, is a lot easier. And folks are doing them more and more. Or checking out Yelp.
Cycles and More of southern Louisiana, over a year later, in a simple Google search pulls up Ambulance Drivers blogpost as the sixth result - and gee whiz, it sure wouldn't inspire me to rush right over and do business with them. For a long while, AD's post was *first* in Google listing for Cycles and More.
Our second example, T&J Towing out of Michigan, when googled generates the Facebook UnLove group dedicated to them and their practices as the FIRST result. Again, not a really great business promotion.
If it's not screaming obvious yet, the wrong thing to do is get all pissy about matters. If you are at fault, or could reasonably be viewed as such - think very seriously about apologizing, then making the matter right...or you, too, could be watching your business implode as the offended customers version of events blazes across the internet like a wildfire on a gasoline-soaked prairie.