A charge of insulting behaviour and another of abetment by conspiracy to cheat were tendered against the owner of Mobile Air, Jover Chew Chiew Loon, at a pre-trial conference yesterday.

This brings the number of charges the 33-year-old faces to 28.

The charge of insulting behaviour states that he made a customer, Ms Zou Jing Tong, pick up coins amounting to $547 from the floor of his shop in Sim Lim Square on Oct 28 last year.

The amount was in part satisfaction of an order made by the Small Claims Tribunal.

If convicted of insulting behaviour, he can be fined up to $5,000.

The other fresh charge accuses Chew and one of his staff members, Kam Kok Keong, 31, of conspiracy to cheat customers.

Kam, 31, is said to have tricked Ms Zou, who is from China, into believing that an iPhone 6 Plus would be sold to her for $1,600, which he knew to be false, and induced her to give him $1,600. He now has nine charges against him.

Chew, who gained notoriety last November after a video of a Vietnamese tourist begging for a refund went viral, was charged in May with cheating 25 customers of a total of $14,449 between January and October last year.

He has also been accused of threatening to have a customer's work permit revoked if he did not pay the now-defunct Mobile Air $600.

Three other staff members have also been hauled to court on cheating charges. Koh Guan Seng, 38, faces 15 counts involving $9,789; Lim Hong Ching, 33, faces two counts involving $1,600; and Kelvin Lim Zhi Wei, 32, faces one count involving $330.

The next pre-trial conference for the five men is on Aug 27.

The maximum penalty for cheating is 10 years in jail and a fine.