My back glass broke

Sean, this is the repair forum, and the iFixit Store personnel don't generally hang out here keeping an eye out for store-related issues. You can use the site's customer service form here.

https://www.ifixit.com/customer-service-...

Or you can email them at support@ifixit.com.

It's certainly worth a try to contact them, but honestly I wouldn't hold your breath on getting a replacement. I'm having a hard time seeing how it's their fault you broke the back when installing it, but then again I don't know the full story.