Can't login with Steam

Hello,

I used my Steam account a long time ago to play SWTOR. At the time, it was associated with a different email that I've since deleted. I eventually changed the email on my Steam account.

Now, when I try to log in via Steam, I get the error:
"We can't log you in. Please double-check you're using the Steam account you usually play on and try again."

I believe this is happening because my current Steam account is still linked to an old SWTOR account I no longer have access to. I don't remember the username or password, and I can't recover it because the email is gone.

That said, I'm more than happy to provide any proof necessary to confirm that I own the Steam account and that it has previously been used to access SWTOR.

I was hoping there's a way to unlink the current SWTOR account from my Steam account, so I can either relink it properly or start fresh.