Hey there, unfortunately not. Access to a Bungie Account requires authentication to one of your linked platforms, meaning someone has got hold of your Steam, PSN, or XBox login and password. It is these accounts that need to be secure, with unique passwords and 2FA. Bungie holds each of us responsible for the security of our own accounts. As of March 2025 platform accounts can no longer be unlinked from Bungie Accounts - Bungie have not made any exceptions to this policy and will not unlink accounts on their end under any circumstances. While it won't help with the current situation unfortunately, you said you don't know how it happened, but you ought to find out or your accounts will never be safe. Change your current passwords at least.