@dekkerclan In this case I believe that you likely do have an EA account, just one that's gone quiet. It's been a minute since dealing with anything ME3-related but I believe an EA account was mandatory, even if it was just quietly linked the forgotten about.
Can you log into help.ea.com using the Xbox portal? That should then put you on some form of EA account, at which point you can try the aforementioned password reset.
You can review (or update) account details on this page too: https://myaccount.ea.com/cp-ui/aboutme/index?gameId=ebisu