参考词汇：路由器router 服务器server 掉线lose connection to 稳定的stable
I am writing to you to complain about ...
I am writing to express my dissatisfaction/disappointment/concern about ...
I am writing to inform you that I am dissatisfied with ...
I feel sorry to trouble you but I am afraid that I have to make a complaint about ...
I wish to draw your attention to the problem/fault ...
I regret to inform that ...
I will appreciate it very much if you could ...
I look forward to your dealing with these problems without delay.
I hope you will consider my suggestions and improve the situation as best as you can.
We hope that you will consider this matter seriously and make an effort to prevent the recurrence of this kind.
I hope you can give me a satisfying reply and deal with this matter reasonably.
I must have you fully understand that without a satisfying solution， I will reserve my right to take legal action.
The reason for my dissatisfaction lies/consists in ...
Under these circumstances， I find it difficult to ...
For one thing ...， for another ...
Therefore， I hope to change for another ... or declare a refund.
I recEived such poor service that I felt I should bring it to your attention.
Dear Sir or Madam，
I am writing to you to complain about the router which I bought last week from the internet.
I found some problems during I use it. First， I can’t find the servers when I looking through the news. Second， it was often losed connection to the servers if I was finding some informations from the internet. It caused big problems to my work and daily life. The most serious doubt is the WIFI doesn’t stable. Sometimes it lose connection to the server in a second. After a while， it come to be fine.
Because of the problems， I requi本文由论文联盟http://www.LWlm.COM收集整理re to full require or change a new one. If you can change a new one， it will be the most wonderful way to solve these problems.