How to unlink my EA acc from lost Steam account

How can I unlink my EA account from my old Steam account, to which I no longer have access? I unlinked my EA account in my account settings, and now the 'link' option is available. I am trying to link a new account according to the instructions, entering the code from my email, but I receive a message saying that this EA account is already linked to another Steam account, even though there are no Steam connections in the 'Connections' tab of my account settings. How can I unlink my EA account from my old Steam account, to which I no longer have access, and link it to my new one?