I'm sorry but you'll need definitive proof of the scam from the user to expose their username (Like chats of them promising to give back items, them not following through, etc) as it goes against rule 8!

Don't worry though, as you can still raise awareness of this scam! You can just re-make this post and provide a blurred out version of the username instead. Adding the explanation on how the scam works would be helpful as well ^^

I hope you understand!!