~But, it's been bothering me since then... What logged in in my account and made these bets? My best guess is a hacker but I'm quite a tech-savvy person and I know my way around secure passwords and decrypting passwords and mine was as secure as it gets (12 digits long, alphanumerical, both Upper and lower case letters plus a symbol) so brute forcing is not an option... My other guess would be a leak from inside freebitco.in but I'd like to trust that you people know what you're doing.... So... What was that?!
When people contact me with this story at the time it happens and identify the account involved I check the email log. In most cases, their email account was used to change the password and authorise the login. All the others are either due to using weak passwords or the same password on other sites or malware or malicious apps. Even 2fa will not protect you if someone can hijack your already logged in session by stealing your cookies.