We've got you covered with 25 customer apology letter templates so you can swiftly say "I'm sorry" and start delivering a solution. Get 4 email templates you can send out to customers when their order is delayed due to production issues.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. Example: "We truly regret any inconvenience this has caused you. It was our mistake and we take full responsibility for it. Why am I receiving a backorder letter? You are receiving a backorder letter because the item you have requested is currently out of stock. Be specific about what you're apologizing for, and use the same phrases and words that your customer used. Say that you are sorry and regret that you could not deliver the order on time,and tell them why it was not delivered on time.