【正确答案】Dear Manager,
The focus of the complaint is the impatience of your shop-assistant whose badge number is 15. For one thing, the assistant turned a deaf ear to our request and walked away. For another, she murmured in a sarcastic manner that my friend was foolish in making such a request. Under these circumstances, I found it so unbearable to face such an awkward situation. Honestly speaking, the products in your shop are of good quality. But you should make great efforts to look into your service and take steps to prevent a similar recurrence of such offensive behavior in the future. All in all, there is still much room for improvement.
I do hope you can pay great attention to my complaints. Thank you for your time and kind consideration.