Don't make fun of your compatriots. it is easy. ask the police in China not only to track the VoIP but also illegal recruiters . ask the Chinese goverenment to be strict sending Chinese workers over unless they have all proper documents. Cambodia government also be strict. with Chinese companies. never let them operate unless their papers and must prove they have funds and that money should be lock by Cambodian govt. to pay up the Chinese and Cambodian employees in case the Chinese leaders run away.