Your company may have a strict social media policy, but that still doesn't make it immune to Facebook, Twitter et al's special brand of justice.

Consider the case of Evergreen Entertainment, a chain of seven cinemas in Minnesota, South Dakota, and Wisconsin, which is suffering a several-thousand-member-strong Facebook boycott thanks to a problem as old as business itself: How to handle customer complaints gracefully. (Here's Benjamin Franklin on the subject back in 1749: "If customers slight your goods... do not affront them: do not be pert in your answers, but with patience hear, and with meekness give an answer; for if you affront in a small matter, it may probably hinder you from a future good customer.")

It all started last week, when Sarah Kohl-Leaf of Minnesota, her husband and another couple headed to a 9:40 pm showing of Shutter Island at the St. Croix Falls Cinema 8 in St. Croix Falls, Wisconsin. Kohl-Leaf and her husband had only brought enough cash for snacks, but the theater didn't accept credit or debit cards for tickets and the lobby's ATM was out of cash. So far, so solveable – the couple's friends wrote a check.

But then the theater staff needed to check for eight underage patrons who'd apparently sneaked into the R-rated film, and so spent about the first 20 minutes of the film wandering through the aisles with flashlights, examining ticket stubs – and distracting Kohl-Leaf from Leonardo DiCaprio.

When she got home, she wrote a strongly-worded letter of complaint to the cinema owners. "I did not pay $18.00 to have a distracted experience," she wrote. " ... I would rather drive to White Bear Lake, where they obviously know how to run a theater than have this experience again."

The response that greeted her the next morning: "Go f*** yourself. If you don't have money for entertainment, get a better job, and don't pay for everything on your credit or check card," wrote Steven J. Payne, the company's vice president. (To read the whole letter – warning: expletives abound – click here.)

Payne also sent a subsequent, calmer email: "As vice president I should never have reacted that way, no matter how I felt about your e-mail."

But it was too late. Kohl-Leaf posted the e-mail exchange on her Facebook page and friends followed. The next thing you know someone created a "BOYCOTT St Croix Falls Cinema 8" page. As of Tuesday morning, it had 5,082 members – more than two times the population of St. Croix Falls. (Payne did not respond to an e-mail seeking comment. He is the subject of a "We support Steven Payne" group, but it has a mere 177 members.)

The public outcry led the company to post a letter of apology on its website: "The officer in question has acknowledged that he made a serious mistake and has apologized for his conduct. We hope that you will accept our apology as well."

This may be an extreme example – most people dealing with customers wouldn't write a profanity-laden e-mail (or if they did, they wouldn't hit the send button). But it's worth keeping in mind that November 2009 research by Covergys, a Cinncinnati company that provides call-center services, has shown that a bad review on social media can cost a company about 30 customers. How did they get that figure? Some 45 people view each remark and about two thirds of them avoid the brand being criticized.

Bottom line: If the customer isn't right, don't say so in an easily forwardable format. Or better yet (and simpler): Mind your manners.

What do you think? How would you handle a customer complaint? And would you discipline a manager who sent a profane e-mail to an unhappy customer?