I accidentally bought the core subscription and then bought the complete. Not only can I not figure out how to get a refund for the core subscription but now I'm not getting the complete game after I paid for both!
I assume you are the same player that posted on discord around the same time with similar wording (which has in the mean time been resolved).
If not, please send me (via response here or direct message) your in-game name, so I can check what happened.