Hey there, I believe you would still have an EA account while playing on the PlayStation 4. All your data during online gameplay would be sent through to EA servers. Things do get a little bit tricky if you are unsure on the details of this account though.
The current suggestion to resolve the "This account is invalid" issue would be to create a new password for your EA account. You can click this link here and try inputting some of your usual email addresses into this to see if you receive a forgot password email from EA. If that works and you get a new password, it should let you back into the game. If it doesn't, give that process another try after 90 minutes has elapsed.
If after all of that, you're still not able to log in OR you're unable to locate your EA account in the first place, I would suggest you contact EA Help via the contact us option here, leave a short description of your issue and the team will get back to you as soon as possible to try and identify your account / get you back in.
Little bit of a tip, some of the EA Sports games do actually show the email address assigned to your account from within the game. Here are a list of titles where you may be able to find your email easier.
Goodluck, hope you get back into the game (online at least!)
PS: As a gentle reminder, keep your personal information safe and only disclose any identifiable details via EA Help :)
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