Crooked retailers have been served a warning after a judge jailed four Sim Lim Square scammers.

The freelance salesmen worked for the collapsed Mobile Air mobile phone shop for notorious conman Jover Chew Chiew Loon have been sent to jail for between four and 14 months for their part in duping customers of a proven $16,147 between April and October last year.

Chew goes to trial next week.

According to a Straits Times court report, the four convicted are Koh Guan Seng, 38, (14 months); Kam Kok Keong, 31, (11 months); Lim Hong Ching, 34, (six months); and Kelvin Lim Zhi Wei, 32 (four months).

The newspaper reports they would lure unsuspecting customers with attractive pricing for new phones, then add hidden charges to extort additional cash from the customers. Such charges included bogus extended warranties

Mobile Air is the store featured in footage which went viral on social media last November showing a Vietnamese tourist who used his life savings to buy his girlfriend a new phone begging for a refund after he could not pay an extra $1000 demanded for a ‘warranty’ before he could take the phone away.

District Judge Toh Yung Cheong said that while they had been trained in how to dupe customers, the four convicted had made conscious decisions to offend.

“In committing the offences, they behaved like thugs rather than sales assistants and they must bear personal responsibility for their conduct,” he said.

Prosecutors said the victims were mostly foreigners on low wages and with limited English skills – thus easy targets for the conmen.

The judge noted their actions had caused wider harm by damaging the reputation of Singapore as a tourist and shopping destination, apart from the impact on Singapore’s retail industry.

The Straits Times’ extensive report on the trial can be read here.