As I understand it you payed with western union.

Cant you just charge your money back with western union?

https://thewesternunion.custhelp.com/app/answers/detail/a_id/52/session/L3RpbWUvMTM4ODQwMzE2MS9zaWQvdDJsVHE2Smw=

Sounds like you get at least the ID of the person who got the money from WU and with that you can file a charge.