The only purpose of ‘customer service’…
is to change feelings. Not the facts, but the way your customer feels. The facts might be the price, or a return, or how long someone had to wait for service. Sometimes changing the facts is a shortcut to changing feelings, but not always, and changing the facts alone is not always sufficient anyway.
If a customer service protocol (your call center/complaints department/returns policy) is built around stall, deny, begrudge and finally, to the few who persist, acquiesce, then it might save money, but it is a total failure.
The customer who seeks out your help isn't often looking to deplete your bank account. He is usually seeking validation, support and a path to feeling the way he felt before you let him down.
The best measurement of customer support is whether, after the interaction, the customer would recommend you to a friend. Time on the line, refunds given or the facts of the case are irrelevant. The feelings are all that matter, and changing feelings takes humanity and connection, not cash.