Hijacked EA Account.... apparently

Hi

I bought Battlefield 6 today for my PS5 - I have other EA games but this one seems to have a new level of security on it. I've had a PS4 for 10 years and my PS5 for about a week. 

Once installed it's asking me to authenticate to an email address which has a .de suffix. I am in the UK, never been to Germany, don't speak German and no clue where this has come from. 

I contacted EA support to explain the situation and provided evidence of my account ownership with email info etc. all 5 instances they terminated the chat saying there was nothing they could do 

When I try to link my EA account to my PSN account it gives me the same error  

Your accounts can’t be linked because your PlayStation™Network account Daddypig995 already linked to your EA Account for gu*****@web.de

I'd be grateful if anyone can advise what do to do - the support routes don't seem willing/able to help me, I have provided what I would say is sufficient evidence and I am authenticated on EA account using my Apple ID, Facebook but can't do PSN - 

Thank you in advance!