We don’t know who you are, 但应该是上司，正式点保险。
1-2-3
Dear Miller
In reply to your recent memo, please accept my sincere appreciation for your contribution to achieve this outstanding result. We all understand that we cannot have this accomplishment without a solid collaboration among all departments involved. So please pass my appreciation to them.
With this month’s sales volume, we have every reason to look forward to a further success in the future.
Best regards
Mike
P35应对complaint
对客人， 一定是客气加正式
dear
We regret to know that you have quality problems with our product, which is not up to our usual standard. It would be helpful for us to find out the problems if you can deliver them back and we will cover the freight for you.
You will be informed of the problems by post as soon as the product examination is finished.
Best regards
Mike