Email already exisit and change admin email

Hello,

I created a email called mysag@mysag.com.br and after I removed it, because I'd like to use this email as a group.

But when I try use this email returns to me a message with this email already exists.

Also, I'd like to know if i can change the admin email to vinicius@mysag.com.br and use the email admin@mysag.com.br in a group too.

Thanks