Who can help me correct the sentances?thanks for your help.

Dear Sir or Madam,
I venture to complain about the poor quality of the electronic dictionary that I bought last sunday at your online store.

I bought a electronic dictionary at your online store last Sunday.

(我大概知道你想说： 我冒昧的抱怨上周日从您的网站购买的质量差的电子词典。 我不建议你一上来就这样说，网购出现问题时， 应该先陈述什么时候买的，买的什么产品。)

I would be appreciate it if I have a good solution to the problems facing me. （这句话放到后面说。）

During three days when the electronic dictionary in my possession,problems of the program have emerged one after another.

But there are problems keep showing up during these three days when I use it. 

For one thing,the scree is always turn off when I am using the electronic dictionary,making many troubles to my study.

For another,the battery in distressing as it supports the electronic dictionary operation for only 30 minutes.Therefoer I wish to exchange it for another new one or declare a refund.
thank you for your assistant if my problems receive due attention.

The problems are:

1. The screen always turn off when I use it.

2. The battery can only keep the dictionary running 30 mins. 

The problems are really disturbing my studying, so it would be appretiate that you can solve the problems that keep showing up. 

I would like to exchange it for a new one or declare a refund.

your sincerely,
LiMing

重新整理：

Dear Sir or Madam,

I bought a electronic dictionary at your online store last Sunday. But there are problems keep showing up during these three days when I use it.

The problems are:
1. The screen always turn off when I use it.
2. The battery can only keep the dictionary running 30 mins.

The problems are really disturbing my studying, so it would be appretiate that we can find a way to solve this situation. 
I would like to exchange it for a new one or declare a refund.

Thank you for your attention, and patient.

your sincerely,
LiMing

出现质量问题的时候， 尽量简短，阐述清楚购买时间，地点和问题。 以及你所想的解决方法。 虽然没在前面说电子词典的质量差，但是你后面说到它出现的问题，已经让质量差变成了事实。 而且想想看email 的人，如果你上来就说我得抱怨你们的产品质量是多么的差， 人家也不会给你一个好的态度， 当然这也是我个人的观点。 重点是把事实说明，然后告诉他们你想要的解决办法。

希望能帮到你！

\Lilly

Who can help me correct the sentances?thanks for your help.

Dear Sir or Madam, to whom it may concern,
I venture am writing to complain about the poor quality of the electronic dictionary that I bought last sunday at your online store. I would be appreciate it if you would porvide  I have a good solution to the problems facing me.
During for three days when the electronic dictionary that I purchased  in my possession, problems of the  with the program have emerged one after another. For one thing, the screen is always turning off when I am using the electronic dictionary, making many troubles for me when I  to my study. a another issue is the battery is in distressing as it supports the electronic dictionary operation for only 30 minutes.Therefoer I wish to exchange it for another new one or declare a refund.
thank you for your assistant if my problems receive due attention.


your sincerely,
LiMing

I hope you get it taken care of

Who can help me correct these sentences? Thanks for your help.

Dear Sir or Madam,
I venture wish to complain about the poor quality of the electronic dictionary that I bought last Sunday at your online store. I would be appreciate it if I could have a satisfactory good solution to the problems facing me I have experienced.
During the three days while the electronic dictionary has been in my possession, problems of the program have emerged one after another. For one thing, the screen is always turning off when I am using the electronic dictionary, making many troubles to disrupting my studies. Also For another, the dictionary can be used for only 30 minutes before the battery runs out. Therefore I wish to exchange it for another new one or declare request/demand a refund.
Thank you for your assistance and I trust/hope my problems receive due attention.


Yours sincerely,
LiMing

My corrections only address the use of English in the letter i.e. where the English you have used is not correct or where the phrasing sounds unnatural. Lilly’s suggested structure for this kind of letter seems sound but as she left some of the English errors untouched (and introduced some new ones) I have just focussed on this. One thing to note (that may not be that obvious in the corrections) is to remember to add a space after a full stop or a comma.

By convention if you do not know the name of the person you are writing to, and you begin with Dear Sir or Madam, you would end your letter with "Yours faithfully". In email correspondence this is less strictly adhered to though.