Option 1: Remove content immediately
Heyevent gathers and recommends Public events from Facebook. Therefore, the easiest way to remove the content from Heyevent, is to remove the content from Facebook.
Once you've done this, you only need to verify that you're not a robot and push the following button, and the content will be removed from Heyevent immediately:
Option 2: Submit a removal request
If you don't have control over the content on Facebook, or don't want to make the content non-public, but still think that the content should be removed from Heyevent, you can submit a request for the content to be removed.
Removal requests are reviewed manually, and should normally be handled within 96 hours.