Blizzard might have the worst customer support

I play Xbox Game Pass on PC. I started playing Diablo 4 from Game Pass on an account that Battle.net had randomly generated for me since my Xbox and Battlenet accounts weren’t linked yet. I’ve put over 100 hours on D4 when yesterday I figured I’d link the accounts for convenience. But now that’s locked me out of the account that I was playing with in the first place with no way to get it back. Support says there’s nothing they can do to help recover the account or allow me to access it. 100+ hours down the drain and now I can’t play my favorite game.