I want to delete my old email and use my new email and trying to update but old email keep coming back

I m having trouble with a person not speaking well English . I had fraud on my bank acct and my phone has all info. And I deleted old email and create all new gmail address. Now on my ipad I create new email address. And how will I delete my old email and use my new email, I can't even update cuz my old email still there. Please help me.