帮我看看有没有语法错误,

帮我看看有没有语法错误,
投诉信
Dear Sales Manger,
I,the undersigned,am a senior in the Computer Science Department of Tsinghua University.I feel bad to trouble you but I am afraid that I have to make a complaint about the book which is entitled Practical Writing and Reading for NETEM.
The reason for my dissatisfaction is that the book is a pirated one.In the first place,much of my valuable time and energy have been wasted in reading the book since it is quite hard to identify many words in the book.In addition,I have not benefited from reading the book since some of keys to the exercises are misprinted.Under these circumstances,I find it very necessary to tell you these problems.
I appreciate it very much if you could change a new one,preferably return all the money back to me,and I would like to have this matter settled by this month since the examination is around the corner.
Thank you for your consideration and I will be looking forward to your reply.
Yours sincerely
Li Ming