Have you ever been criticized when you're actually innocent?
Often, when we're criticized, there's a nugget of truth in the critique. That nugget of truth makes the critique easier to handle. You may not agree with everything that person has to say, but you've got a piece of common ground to start a dialogue.
But what do you do when the critique is all the way off?
Make an effort to listen. Even if the person is mistaken or wrong, it does your soul good to show people respect.
Resist the temptation to pretend like the critique is justified. Nodding and smiling may make the criticism end earlier, but it won't do your soul any good. At best, you'll become a little more fake in a world that tries to make us more and more fake every day.
Defend yourself. We so rarely find ourselves innocent. If you are, push back gracefully and forcefully.
Be careful. There's a chance you're not as innocent as you think you are.