Write an apology letter to the customer

You are the manager of a restaurant that has received a letter of complaint about poor service from a member of your staff.
Write a letter of apology to the person has complained. In your letter:
- Say how sorry you care that the person has had a poor experience
- Explain what action has been taken against the staff member
- Offer a free meal for four people at the restaurant as a gesture of goodwill.

bad service during birthday at restaurant

Dear Mrs.Smith,

On behalf of ABC restaurant, I wish to express my sincerest apologies towards the unsatisfactory you encountered at our restaurant on Monday evening, January 25th, which was an association with our team member, John.

I could imagine and understand how furious and irritating you experienced at that time. You had selected our restaurant to celebrate your birthday, but John, one of the servers, deliberately ruined your best moment when declining to pack your food. His bad-mannered and poor-behavior was inadequate in term of the restaurant's scopes, which prioritize guests' satisfaction, and he has now been suspending from work for seven days. As a manager in charge, I would like to take responsibility for his attitude and assure to re-trained him concerning customer service.

I am grateful that you brought the matter to our consideration and I ask your forgiveness. Your feedback is the most significant information that worths attention. I have enclosed a free meal voucher for four people, provide you visit ABC restaurant next time as a thank-you.

We hope to see you again.
Sincerely,
Han Nguyen Assistant Manager

Hi, I think you did a great job of addressing the points in the prompt. You did have some incorrect verb tenses though and a couple of other errors:

the unsatisfactory service you encountered ... which was in association with ... {"association" sounds odd to me though - maybe "... 25th, in your interaction with our team member ..."}

... how furious and [irritated] you must have been with your experience at that time. {or "... understand the anger and irritation you experienced ..."}

... ruined your best moment [by] declining to pack your leftover food. { or "to pack you a to-go bag"} is this what you meant? It was a bit unclear to me} His bad manners and poor behavior was inadequate in terms of the restaurant's commitments, {or "principles"} which prioritize

... he has now been suspended from work ...

... for his attitude and assure you we will re-train him concerning ...

... Your feedback is extremely significant information that merits attention.

... for four people, provided you visit ABC restaurant next time {this sounds a tiny bit rude to me - maybe "... for four people for your next visit to ABC ..."} as a thank-you.

... Sincerely,
Han Nguyen, Assistant Manager