1．投诉信的开头常用句式
I am writing to you to complain about...
I am writing to express my dissatisfaction with ...
I'm sorry to bother you but ...
2．投诉信的主体常用句式
There are some problems with...that I wish to bring your attention to.
I can hardly bear/tolerate/put up with it any more.
It's not what I hoped for.
I'm not at all satisfied with...here.
I'm really very annoyed about it.
