Successfully addressing customer complaints is an essential part of customer service, and the interviewer wants to hear that you are okay talking through a customer's complaint. Start off by telling the interviewer that you do not mind addressing customer complaints, and you recognize that most customers have good intentions when coming forth with a complaint.
Tell the interviewer that you take time to listen to everything the customer has to say first to ensure you truly understand what they are upset about. Next, share that you make eye contact with the customer and sincerely apologize to them. Finally, be sure to mention that you offer to correct any mistakes that were made or take the appropriate action to rectify the situation.
"I handle customer complaints very well, and usually quite quickly. I understand that every upset customer wants to know that they are being listened to, and I do that very well. My listening skills are strong, and I can make suggestions for a resolution that works well for the customer, and my employer."