A construction contractor, angry that a Grab driver broke an appointment to return a mobile phone he had left behind, threatened the driver with a car steering lock and got into a fight with him.

Yesterday, Malaysian Ng Seng Hui, 28, was sentenced to five months' jail after he admitted to criminal intimidation, affray and drug consumption. A mischief charge was taken into consideration during his sentencing.

It all started on June 2 last year, when Grab driver Muhammad Asrul Ja'afar, 25, picked up Ng and his Malaysian friend, Chai Kim Onn, 24, a court heard. At his destination, Ng got out but left his mobile phone behind.

The next day, Ng contacted Asrul and suggested that the driver bring the phone to a hotel in Geylang where he was staying.

Ng also offered to pay a small fee to Asrul, who agreed to deliver the phone that evening.

Ng became upset when the Grab driver later asked to postpone the delivery, as he received a "high fare" job in Jurong.

Two days later, Asrul went to the hotel to pass the phone to Ng. Chai took the phone and passed $25 to Asrul, whose wife was also in the car.

At that point, Ng appeared with a car steering lock and demanded that the driver get out of his car.

When Asrul, afraid that Ng might hurt his wife, refused to do so, Ng hit the car with the steering lock, leaving a dent.

Asrul got out of the car and a fight broke out between the two men. Chai joined in the fight and hit Asrul with a vehicle breakdown sign.

A passing motorist separated the three men. Asrul later made a police report.

The case against Asrul, who was charged with affray, is pending.

He incurred $750 in repair costs and more than $8,000 in medical fees for a right knee injury which required surgery.

Chai has been fined $2,000 for fighting in public.

Ng, who admitted to taking drugs on March 22 last year, has a previous conviction for affray.

Correction note: An earlier version of the story wrongly stated the amount of Chai's fine. This has been corrected.