The right response to feedback is, “thank you.” Or perhaps, “that’s a great point.” Even if it’s not your job to change the system, or not your fault that things didn’t work as expected, both of these responses are valid and useful.
Feedback is a gift. It lets you know precisely what the other person wants or needs. After you receive the gift, it’s up to you to accept it or not. But shutting down feedback with an argument or by appearing ungrateful makes it less likely you’ll be offered it again. And if you’re getting feedback from a customer or a prospect, shutting it down makes it likely that they’ll walk away and take their attention and their trust somewhere else.
When you say, “no problem,” you’re letting yourself off the hook, refusing to acknowledge what was said and closing the door for a useful interaction. Because there is a problem. Exploring what the problem is is far better than denying it.