It's an scam accusations topic or reputation topic I think.
If you are sure about what you are saying then collect evidences and post it in the scam accusations board.
Here is the proper format
[b][color=black]What happened:: [/color][/b]
[b][color=black]Scammers Profile Link: [/color][/b]
[b][color=black]Reference Link: [/color][/b]
[b][color=black]Amount Scammed: [/color][/b]
[b][color=black]Payment Method: [/color][/b]
[b][color=black]Proof of Payment: [/color][/b]
[b][color=black]PM/Chat Logs: [/color][/b]
[b][color=black]Additional Notes: [/color][/b]