投诉英语怎么说,用英语写一份投诉信，该怎么写

投诉英语怎么说,用英语写一份投诉信，该怎么写

(右上角)Dec 日期
(左上角)Dear Mr.Manager:
（起一段,空两格）,I’m writing to complain about the poor quality of mobil phone in your store.I bought an SQ200 mobile phone at The First department store.The mobile phone couldn't sent message and take photos after a short time.I hope The First department store can exchange a new one with me or return me the whole money.（起一段,中偏右）Yours,（起一段,对齐上排）作者名字、
一个例子供参考：
Dear General Manager Mr.XXX
With all due respect, I am writing to you a serious letter to get either refunded or exchanged on a washing machine purchased at your department store on 17th, May.
Only two week from the date we made the purchase, the machine was no longer functional and remained broken after being repaired again and again. I suspect the authority of the salesperson to make the decision, and therefore I am turning to you for your kindly help.
Sincerely
XXXXXX祝开心喔~