Multiple linked devices on my account

Hello, I need help with unlinking an intruder on my swgoh account, I have contacted EA support but they are unable to help. I have an Iphone so my IOS login brings me to my account, however when I go to bed it seems someone is logging into a different device to play, I havent played the game in maybe 6 to 8 months, therefore I know someone is logging in through another phone. I have changed the ea account linked to the game however its no use. Please help me get them off the account, it seems like they have been there a while just undetected.