英语作文关于营业态度的投诉信

Dear Sir or Madam,
I am writing to let you know the deplorable attitude of one of your staff members.
I received my telephone bill for the previous month and found there were some mistakes in calculation： I had been overcharged for 3 long-distance calls. However, when I called your Complaints Department, the girl who answered my phone was very rude. She interrupted me continually and even said it was my fault. Such a way of communicating with clients is unacceptable.
I would like to suggest that you look into the matter as soon as possible and ask the girl to make a formal apology to me. An early response will be appreciated.
Sincerely yours,
LiMing