Hey @Superstan47,
If you're having trouble signing in you can try updating your login info with these steps.
If that's still not letting you login afterwards, please reach out to an advisor so they can look through the account with you.
Once that's straightened out you should be able to link your Xbox account to your EA account with these steps, though keep in mind that your progress is separate on each platform and would not be shared between Xbox and Switch for example.