"I got a letter n the mail but there was nothing in it. The envelope was ripped open. I realize that ... " (more) this is not your fault so I'm still giving you a positive rating, but I just wanted to call this to your attention."
"I am so sorry that this happened. I figured that since the earrings were so small that it would be ... " (more) fine. Let me know if there is a way that I can make it up to you because that is definitely not fair to you."