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If they're asking for passwords, what you'll want to do is go to the main forums, down to the report forms there, and report the USER- not the thread.
Make sure you take a screenshot or provide a link to the thread in question within the guild so that the mods can see what you're talking about.
Do not report the guild as the guild its self is not actually at fault, and it would go to the wrong report queue- and guild crew (active or not) can only ban the user from the guild. They can not take corrective action such as official warnings or site-wide bans, so I do not recommend alerting them either aside from to lock the topic and move it or delete it from the guild.
To report a user directly, you will go to Forum Index > Scroll to the bottom > Click 'Report Harassment or Abuse' and fill in the persons username and then provide as much relevant information as you can. Without links or a screenshot, the moderators will have difficulty processing the report quickly and may contact you for more information.
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