Here are some things to think about:
• Your letters will be in response to a complaint letter from one of your classmates. Because of this, you should keep in mind the very real audience of your adjustment letter: the person who wrote the complaint in the first place.
• Obviously, you will have to take some liberties with the facts in how you answer these complaint letters since you (probably) aren't affiliated with the company organization to which the complaint was directed. I'd encourage you to be creative, but don't be too creative (for example, don't blame the mishap on aliens from outer space.)
• We will have a peer review for this assignment.