Unable to unlink my EA account from Xbox because two accounts are linked

My sister bought split fiction lastnight so we can play and we discovered my EA account is linked to her Xbox account and my account so the option to unlink in connections is not showing up in the Xbox section. She is unable to  connect her EA account in order to play through friend pass. Iv had multiple chats with EA support with no help to resolve issue it’s just been a continuous loop with no results and EA is saying they can’t do anything, but I can’t also do anything it’s very disappointing and very frustrating she wasted money on a game we looked forward to playing and are unable to because of EA not being able resolve an issue which is on their end it’s a simple issue we just want the accounts unlinked so can have her own EA account linked to her Xbox account.