Linked EA and swtor accounts can now have separate emails and passwords per https://help.ea.com/en-us/help/star-wars/star-wars-the-old-republic/swtor-account-linked
that is possible there is another swtor account , back when they switched to username, i did see a number of people with other accounts when the change occured
the best way to find/confirm the original account is to call swtor support when the lines open
Support said to add a new email , validate and then switch back to the old one
that account has characters dating back to 2014, they said its an old account but not much played on , although it has a steam account linked to it when it came out
they also said there maybe a 2nd account but best to call so they can look further
