RE: Do YOU have 2FA enabled? Do you use a password manager? The convenience of cutting these corners is NOT worth the risk!

[ashaman]

Did you reuse the password on that account anywhere else? Then that's the likely vector for how this was possible. However, if you can't establish an attack vector through which someone may have been able to do this, you have to seriously consider the possibility that one of your devices has been p0wned.