Using a list of names and NRIC numbers from a community event, a 20-year-old man applied for 49 mobile phone plans online and obtained phones for free or at a discount, cheating a local telco of more than $30,000.

This was just one of four methods Ronny Lee Jia Jie used to cheat others of almost $33,240 from December 2014 to May last year.

Yesterday, Lee, who is serving his national service, pleaded guilty to 16 cheating charges. Fifty other charges of a similar nature will be considered during sentencing.

Deputy Public Prosecutor Teo Yu Chou told the court that in November 2014, Lee volunteered at a brisk walking event held by Nee Soon East Community Centre, where he was given a list of participants and their NRIC numbers for attendance marking.

He then used the list to make 49 mobile line applications on Singtel's website.

"For each application, he would select more expensive mobile plans so he could obtain a bundled mobile phone for free or at greatly discounted prices," said DPP Teo.

Court documents revealed that Lee obtained at least three iPhone 6 Plus handsets for free under a Combo 12 subscription, Singtel's most expensive monthly plan.

He subsequently cancelled 21 applications out of guilt before the phones were delivered, but went through with the other applications and obtained 28 phones worth $30,152 in total.

He sold nine of them to secondhand dealers and on online marketplace Carousell for a total of about $7,000. Twelve of the unsold phones were recovered and returned to Singtel.

Lee has made full restitution to the telco for the nine sold phones and seven unaccounted ones.

The court also heard that between July 2015 and May last year, Lee cheated 11 victims a total of $2,486 on Carousell by failing to deliver items, including concert tickets, after payment had been made to him.

He has made partial restitution to the victims.

In 2016, Lee cheated local courier delivery service FastFast of $518.10 and swindled three victims of $820 through bogus investment scams. No restitution has been made in both cases.

Lee's lawyer, Mr Cory Wong from Invictus Law Corporation, said his client is remorseful and has already made restitution of 84 per cent. Lee will be back in court on Thursday.

For each charge of cheating, he can be jailed for 10 years and fined.