409 means the linked EA account is disabled requiring password reset or has been disabled and data wiped due to inactivity (on rare occasions the reason is the account is banned)
account issues cant be handled ingame even if a subscriber
If you login on the swtor account and go to the cartel coin tab at the bottom of that page is mange billing link, on that page it will display the email address used on the linked ea account
(it is possible you will not be able to access that page due to the issue)
If unable to reset the password on the linked ea account, you will need to call swtor support when the lines are open, they can resolve the issue for you