Supercell ID Email Changed Without My Permission, Account Hijacked

My Supercell ID email was changed without my permission, and I can no longer access my account. I received emails in Russian, and when I tried to log in, my session was closed. I realized that my account had been compromised.

I contacted Supercell support for help, but they have been no help at all. They say that I need to provide the email address or phone number associated with the account in order to recover it. But I don't have access to either of those things!

I'm really frustrated. I've lost eight years of progress on my Supercell games, and there's nothing I can do about it.