Launcher is asking for my registration code again and stopping me from logging on.

[Nekodar]

I bought digitally as well. I cant seem to find the actual registration code, and since Square has shut down all digital downloads of the game I cant seem to get into it to find my code

Have you checked your mail folders, including spam folders?
If you bought from NA SE store, have you tried what someone else in this thread said about www.findmyorder.com ?