are you use the security question ? it's help for lock your account.
The only mod accept is sign message, if you can't sign message from old staked address maybe you can't get it back. let's see the other people will say
Can't they just lock the account if they have reasonable proof it has been hacked? I thought i read something about it, and that it didn't need a signed message, but rather something that could just proof you've been associated with the account. Hilariousandco locks them pretty often i think
For recovering, yea, you're fucked. There's no way to get back in without a signed message..