_________ (Mention recipient’s details)
Date: __/__/_____ (date)
Subject: Apology for _________ (mention details)
This letter is in reference to the complaint that we received from your end on __/__/____ (date) bearing token number _____________ (mention token number).
As per the complaint issued, ___________________ (summarize complaint) and we apologize for the same. We know that the same is intolerable and depicts unprofessionalism and was a sign of ignorance. The same could be avoided and we regret the same.
We apologize for the same and admit the guilt for the same. We would ensure to prevent such happenings in coming future. For any queries, you may reach us out at ____________ (mention contact details).
__________ (Your Name),