Apology letter means saying sorry for what wrong has been done. An individual who wants to accept his/her mistake can write an apology letter. The apology can be verbal or written in this case but if the complaint is formal apology should be in a way of writing.
This letter helps to rebuild personal and professional relationship. Apology letter should be address to the person who has made complain.
Sample apology letter complaint
June 2, 2012
Name/Title Mary Roe
Address 795 E Dragram
City, State, Zip Code Tucson, AZ, 85705
Dear <Customer Name>
I am sorry that you have been charged twice for the product that you bought last Sunday from our store.
I admit it’s the mistake at our end due to computer technical issue. And to avoid such issue we have made new procedure for the payment.
I have I have credited the amount in your account. Sorry for the inconvenience caused to you.
Thank you for writing to us, your opinion has helped us to improve our operation.
Yours in service,
<Company Representative>