Bungie Names can only be changed by the user logging into the Bungie.net website or Destiny Companion app and going to the settings page. There is no bug. If you did not do this then someone has access to your account. Account security is our responsibility at all times. As for the name, we only get one name change. Once used, that's it. Bungie will not offer you another name change no matter what. If you don't have a name change available then you're stuck with that name forever. The good news is, it's just a name and it doesn't affect your ability to play the game at all.