Then channel the feedback to the respective department for follow up action.
It's the best strategy. You answered the customer and take the necessary corrective action. Case closed.
Isn't it expected and boring? If so, why is every doing it?
Well, this is the fastest and easiest way to close a case, isn't it? It doesn't cost you anything as well. Especially if it got nothing to do with exchange or refund. But the more important issue is what goes through the mind of you when you received a feedback/complaint. Another idiot trying to get something for free? An unreasonable request? Another irrational person? Or a customer providing genuine feedback.