Find the topic that you were selling the item/the other person was selling on, and look at the end of the link. The ID should be at the end. Example of where the topic ID is: spam-corner-f35/how-do-i-find-a-topic-id-t35391.html That part in reddd is the topic ID. Hope this helps
THAAAAAAAAAAAAANKS (And Rhett, I actually believed you and went crazy because it wouldn't accet any id .___.)