Final answer:
The key principle of customer service you should not do is ignore the customer's concerns; instead, actively listen, empathize, and focus on solving the problem without assigning blame.
Step-by-step explanation:
One key principle of dealing with upset customers that you should NOT do is to ignore their concerns. Instead, it is essential to listen actively and empathize with the customer, showing understanding of the situation they are in.
By choosing your words carefully and staying as calm as possible, you can prevent further escalation of the issue. It is also important to avoid suggesting that you're right and the customer is wrong, as this can close off communication and exacerbate the problem.
Focus on posing open-ended questions to better understand the customer's perspective and to demonstrate that you're invested in finding a solution. Restating what the upset customer has said can affirm that they are being heard and help to avoid misunderstandings.
Finally, center the conversation around solving the problem, avoiding any blame that could inflame the situation further. If the situation remains unresolved, do not hesitate to seek assistance from a supervisor or HR department.