I have this trouble too. I come back playing epic seven when the origin just came out. I haven’t notice the issue of terminating login support via X so I accidentally connect my new account with X. Maybe there are further information would be great if i can have a chance to chance my login method

Smile Gate removed the ability to log in to Epic 7 via Twitter (X) a while ago. Best thing to do is  contacting customer support with a 1:1 inquiry to see if they can help