Melanie's email account was hacked so she changed her password and set up 2-factor authentication. Now when she logs in, it tells her there's been "too many attempts" and it logs her out. Leo says that there is a Google help chat where she could get it reset. There's also a phone number that she can call. She should check under Google Help.
The problem, though, is that Google doesn't have technical support so it may be an exercise in futility. It's possible that Melanie isn't logging into the right account and that's why she's having that issue. Another thing to try is to start the process all over again in a private or incognito browsing session. She can also reset her browser to get rid of any cookies or login information. Starting from a clean slate could give her a better chance.