Can I get a replacement for a banged up apple case?

Warranties cover flaws in manufacturing. Apple will not replace a used, banged up case for free. It looks that way because you've used it, not because it came out of the box like that.

You have only one option. Buy a new case and throw the old one away.

It should have a standard 1 year warranty (:

All apple cases come with a warranty, so if yours is inside the warranty, Apple can give you a replacement 🙂