@tisnotme I've replied to your question in the other forum post, but for completions sake, I'll add it here too!

Did you get a chance to review the Patch Notes? If not, here they are! I'll quote how you're meant to get your new character slot from 20 to 21:

"3. Character Limit
Server character limit expanded from 20 to 21 slots
One (1) free character slot per server (Kaiator and Velika) will be delivered via Parcel Post when you log in between Tuesday, November 13 and Tuesday, November 20."

I hope this helps!