You are writing a letter of complaint. You need to explain your complaint and use the right tone.

You have attended a fireworks display with your family. Before the fireworks display there was a concert and music. One of the entertainers - purporting to be a "tribute to Robbie Williams" - performed miserably and swore repeatedly to the audience, using the worst language you can imagine. Write a letter to the organisers complaining about the evening. Make your case calmly and soberly. You want an apology and a refund.