Ok I figured it out. They dont explain it well at all but when you sign into your bungie account with your xbox or psn account, you cant unlink the account that you are signed in with. So what happened to me was i switched to play station and accidentally linked my psn account to a different bungie account than the one a I already had with bungie. So if I signed into either account i couldnt unlink it. This is exactly what you have to do. You have to link a google account to whichever bungie account you want to unlink. After that you have to sign out. Then you have to sign back in to that account but do it with your google account. Once you do that then you should be able to unlink your account and then add it to the other one.