What is he even blackmailing you with?
what does he have that you absolutely can not let become public knowledge? If he's "blackmailing" you to get your account back then you're being a dumbass. He will never give it back and you never should have given him any thing to begin with. The loss of an email, gaia account, ect are nothing. Move on and stop whoring out your girlfriend.
There is nothing we can do for you. Gaia staff could maybe help you, but its unlikely it will happen with any sort of speed.