PS4 Account Login Issues

Hi,

I've got a subscription on PC with all expansions and was planning to play FFXIV on PS4 with my sister. I bought the starter edition and tried to login.
On the login screen, however, my PSN name appears instead of my Square Enix account. When I used my SE password I got a message that ID or password are incorrect so I tried resetting. Using the new password ended in the same result.

I tried customer services who provided a form to unlink my PSN account, which I did. This didn't solve the problem though. When I log in the Square Enix site (https://eu.square-enix.com/en) the correct PSN account shows up under linked accounts. Unfortunately that means that this name will be used when attempting to log in on PS4. On Moog the PS4 boxes aren't ticked either.

So I was wondering if anyone on the forums can help with this issue.
Thanks in advance.