That's not a tech support issue, more of an account/billing issue which is the purview of the GM team, typically. Open a GM ticket, provide the account name, the old e-mail address you believe it is, and something else to help us identify the account and we can go from there.
As a security professional would say, "Something you have, and something you know." in the absence of true SSO or MFA options thanks to the age of the game.
GM Ticket system