Hey there, unfortunately if you are unable to authenticate the Steam account, then there's no way to deactivate cross-save. Bungie will not adjust anyone's cross-save or linking on their end under any circumstances. There is no workaround. I don't believe Steam ever deletes accounts without the owner specifically requesting it - getting an account deleted is a lengthy process requiring proof of ownership. So if you didn't delete it, then there might be something more serious going on, or could you maybe not have provided the right details or enough for them to identify the account on their end? I'd recommend giving account recovery another go. May I also ask, why are you trying to deactivate? If you're trying to unlink the old Steam account, this can't be done at all since a policy change in March of this year.