The six debt collectors had gathered at a foodcourt stall in Funan DigitaLife Mall and created a ruckus when its owner did not turn up to repay a purported loan.
Some vented their frustration on the Soup Master stall, causing $880 in damage.
One of the men, Tang Wei Leong, was yesterday jailed for three months for being a member of an unlawful assembly at the Food Junction outlet on Jan 15, 2015.
Tang, 45, and five of his colleagues - all debt collectors from Double Ace Associates - were at the stall that day as its owner supposedly owed food supply company Oregano Trading $21,000.
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Deputy Public Prosecutor Kenneth Kee said: "Double Ace operates exclusively as a debt-collection company that provides debt recovery services to creditors for a fee."
He added that four of Tang's colleagues, Francis Lee Sian Sian and Yong Chee Meng, both 41, Andra Chew Keng Leng, 40, and Lim Boon Tiong, 43, met at the foodcourt at around 1.15pm and confronted a cashier who was manning the stall.
They told her that they were there to collect the owner's supposed debt and would disrupt business if their demands were not met.
DPP Kee said: "The four of them then took turns to stand in front of the stall to chase away potential customers, informing them that the stall was not in operation. They also demanded that the victim call for her boss to come down to the stall to account for the alleged debt owed."
Tang and another one of his colleagues, David Tan, 37, soon arrived at the scene and joined the others. They refused to leave the premises and demanded the money in the till. But management staff, who had rushed to the scene, prevented them from taking the cash.
Tang and his colleagues refused to budge even when police officers arrived at the scene. The six men told the police that they were going to have lunch at the foodcourt.
DPP Kee said: "Seeing that the accused persons were no longer insisting on taking the money found in the cash register, the police officers issued a final verbal reminder to the group before leaving the scene."
Tang and Tan remained at the stall for about an hour before leaving the premises. Their colleagues who stayed behind became violent when the debtor still failed to turn up at around 3pm.
Yong kicked a rice cooker and shoved a cash register onto the floor. Chew threw various food items into a large pot of soup, destroying it.
The police were called again but the four men fled before officers arrived.
Chew, Tan and Lim have already been dealt with in court and were each jailed for between three and five months. The cases involving Yong and Lee are pending.
For being a member of an unlawful assembly, Tang could have been jailed for up to two years and fined.