Click the "My Account" button and input Craigslist account credentials if you use an account. If you don't, check your email for the message Craigslist sent you when you published an ad you believe to have been flagged.
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Scroll through the list of ads you've published while logged in to your account for the past 180 days. Click the name of the one that displays next to the text "flagged." Alternatively, click the link in the email Craigslist sent you to be taken to a page that shows you ad an its current status.