Replying to How should i mess with a scammer?

I recently found out i was about to be scammed - im selling my camera and was negotiating with someone who , after i requested $560, said she sent $680 (for shipping and such) to my paypal account, a spam message showed up saying I have to give a shipping confirmation to get the money. I told her I shipped it just to fuck with her/him but I need some fresh ideas..preferably somehow tricking the scammer that the cops are on them