Why was my topic removed?

You will have received a notification for it on the top right of the page. Moderation will have included a reason behind the removal.

Most of the time it this is due to your post being under the wrong topic.

Ya most common mistakes people make when doing a topic and having it removed are Wrong board placement (eg you wrote this on say Memes and games or any other place than Player Behavior) Naming and shaming is also a big one, did your post have the names of the people you were playing with?

You did not make your post here. Did you post it in another region? You're an EUW player and these are the NA Boards. You may have switched by mistake.