They have a clear understanding that the best time to deal with the complaint is while the complaint is happening. 70 percent of complaining customers will return if the problem is resolved in their favor. That number grows to 95 percent if it's resolved on the spot. A prescription for action Fighter pilots make instantaneous decisions. If they don't they die.
Customer complaints are similar.
If they're not solved on the spot, the customer will probably never return, which is another form of death. Therefore, establish an environment where immediate response is the norm. Cut some slack. Give those employees who deal directly with the customer the freedom and authority to break the rules when the situation demands. That shouldn't be the case.