There are a lot of ways that a hacker can access your account. For one, phishing emails are a tool often used by interlopers. By sending an official-looking email that you're sure to respond to, the hackers have effectively gained your username and password. Usually, this email will route you to a webpage that asks you to sign in to your Netflix account. It's best to avoid signing in to your Netflix account anywhere other than the official application or website. Next, hackers may have gained access to another account of yours. This is why those who know the industry often advise people to use different passwords for every account. If someone gets into your email, they'll also gain access to other accounts.