Yes alphanumeric is one of the best password combinations, but it is your responsibility to secure your account, you should keep it secret so that nobody will know that you are having that thing. You should change your password often as much as possible make it monthly and install a 2FA feature that can send you a text message or email for confirmations But we can never prevent instances that hacker may do something to our accounts it is not our fault but the developer is in charge of it.