Dear Sir or Madam,
As one of your regular customers, I am writing to complain about the poor quality of the electric dictionary purchased in your on-line store that enjoys years of reputation.
The dictionary is really of great importance in the process of my English learning. Unfortunately, I found that there are several problems. To begin with, the dictionary operated well at first, but ten days later it began to make a lot of noise when opened. In addition, some of the keys on the keyboard do not work. I strongly request that you can either send me a new one or refund me in full.
I really appreciate all your assistance in this matter. If you have any problem, don't hesitate to contact me. I am looking forward to your reply at your earliest convenience.