Dear [Name],
I am writing to apologize for the unfriendly staff that you encountered at [location]. I understand that this was not the experience you expected and I am truly sorry for the way you were treated.
At [Company], we strive to provide excellent customer service and it is clear that we failed to do that in your case. We take customer service very seriously and it is unacceptable that you were treated in such a manner. We will take the necessary steps to ensure that this does not happen again.
I understand that this experience has likely left you feeling frustrated and disappointed. I want to assure you that we take your feedback seriously and will use it to make changes in our customer service policies. We are committed to providing our customers with the best possible experience and we will do whatever it takes to make sure that happens.
We are also offering you a [discount/free product/etc.] as a gesture of goodwill. We hope that this will help to make up for the unpleasant experience you had.
Once again, I apologize for the way you were treated. We take customer service very seriously and it is unacceptable that you were treated in such a manner. We are committed to providing our customers with the best possible experience and we will do whatever it takes to make sure that happens.
Sincerely,
[Your Name]