Our free customer apology letter templates and comprehensive guide make it easy to craft an effective customer apology. In this article, we'll cover everything you need to know about writing apology letters and provide 5 templates you can use to get started today.Dear Customer, I apologize for the lateness of this order. It is not the way we like to treat our valued customers. Please let me know if I can make it up for you in any way. Find out what goes into writing effective, heartfelt customer apology emails with these best practices and free templates. Step 1: Say That You Are Sorry. When you open your letter, the first thing you need to do is say that you are sorry. 14 apology email templates ideas and samples to help you acknowledge your error in a way that engages customers and rebuilds trust. Need to write a great apology letter to your customers?