If you're still having a problem with GameStop Digital Download on the PC, here's what I did to get it. So, basically you have the GameStop App on your computer, yeah? Open that up and Click on "My Games" and you should see your FFXIV ARR stuff there. Now, check the bottom right of the app screen, does it say "LOGIN FAILURE"? If so, then I believe the GameStop App couldn't properly update and send out your Collector's Edition Code to you, because as soon as I clicked the Login Fail button, properly logged in... My Games Updated and showed a new icon labeled "Final Fantasy XIV: A Realm Reborn Collector's Edition". Just hover over it, click product code, and voila... you got your goods. So, really they probably did send out all the codes, but it was all done via the GameStop Application and not via email the way it is with people who bought directly from SE or Amazon.

It worked for me, see if it works for you, hope it helps!