Salutations, I am another new member here and have just ordered my first mechanical keyboard.
I ordered components to build a PC a couple of months ago as well, and my case also came with a little bit of damage. It's probably considered minor damage, but my OCD side allows it to drive me crazy. The case is a Corsair 750D and on the front pannel, one of the hinges holding the piece of aluminum in front of the fans came broken. It works fine, but the piece of aluminum sticks out about half a centimeter or two and it compromises the styling because the rest of the front panel is flat and is supposed to "flow" with the piece of aluminum sticking out. I didn't bother to return it because I wanted to build the computer and waiting another week or two seemed a little useless at the time, but every time I look at it my eye starts twitching. Once I fill all the drive bays it will hopefully not be noticeable anymore.
This post quickly got boring and longer than I was planning, but I wish you good luck in your endeavors and I hope you get a replacement case ASAP. Good day.