【正确答案】[参考范文]
Dear Sir or Madam,
As a regular customer of your online store, I am writing this letter to complain about the poor quality of your product--an electronic dictionary I bought in your store the other day.
The dictionary is supposed to be a favorable tool for my study. Unfortunately, I have found something wrong with it. To begin with, when I received it, I detected that its appearance had been scratched. What' s more, I did not find the battery promised in your advertisement, which makes me feel that you have not kept your promise. Therefore, I strongly request that a satisfactory explanation be given and effective measures be taken to improve your service and the quality of your products.
I am looking forward to your reply at your earliest convenience.