My character logged out in an Endwalker area, and now I cannot even log in anymore because the game doesn't think I own Endwalker. I know I am supposed to enter another code, but every avenue I use to enter it tells me the code is invalid.

I can't use mog station to enter it, I can't use steam to enter it, I can't find any way to contact anyone to ask for help, I don't know what to do.