The problem is that they are of no help on this issue. There are several open threads (which have now been closed) about similar issues and I'm here to chime in my 2 cents hoping that something can be done. The rep i spoke with on the phone rushed me off stating the same thing you've stated in other threads about "talking in circles." The bottom line is that we should be able to unlink and re-link our Microsoft Accounts at will just like any other game publisher in existence by simply entering the Microsoft credentials into whatever EA account we'd like. There should be a process of proof to reclaim ownership of linkage should one be needed and I'm almost certain that there was no warning when the link was first made that it would be permanent should the resulting EA account no longer be accessible.
My problem is that I have my Microsoft Account linked to an old EA account where the email domain provider is no longer even in existence, so I am unable to reset that account's password and the one I created years later for my PSN works just fine, but I cannot link my Microsoft Account to it.
The rep at EA told me to speak to Microsoft and maybe they will be able to assist with this. Microsoft told me today that the linkage is completely on EA and they cannot de-link it from their side. I did ask them about a master de-link of all game publishers from my Microsoft account to essentially purge it and attempt to re-link all my publishers, but no one should have to go to these lengths and especially not suggesting as they have for several other customers that they should create a new Microsoft Account only to lose all of their Achievements, Purchases, etc which Microsoft told me that they could not transfer to a new tag. This issue certainly warrants a further look from the BBB and other similar organizations as it cannot be lawful to purposely exile customers this way from playing any EA Games online. I will be forwarding a formal complaint to them about this and hopefully we see a resolution.