Alexandra asks: "How can you turn angry customers into fans?"
Angry customers are people who did not have their expectations met; however, in most cases, the cause of the upset is typically accidental or unintentional and can be corrected.
One suggestion would be to have a manager (or the business owner) contact the customer, recognize the customer's emotions, apologize for not meeting their expectations and reaffirm your commitment to make it right.
Point to note: you should NOT debate, dismiss or disqualify how the customer is feeling. Even if you know that you or your company did nothing wrong - do not make the customer wrong. Recognize their feelings and apologize for their unsatisfactory experience.
In an effort to make it right, you could provide the customer with a token of appreciation for their past business with your company.
An example of a response could be: