SINGAPORE - A cellphone store owner has been fined $21,000 by the Personal Data Protection Commission (PDPC) after he used customers' details without consent to register prepaid SIM cards, which he then sold to others.

Mr Neo Yong Xiang will also be charged with two counts of cheating on Friday (March 11) for alleged misuse of computer systems containing customers' personal data, said PDPC and the police in a joint media release on Thursday.

PDPC was investigating complaints about text messages advertising the sale or rental of property sent to individuals who had registered their numbers with the Do Not Call registry, when it found that a large number of messages were sent from SIM cards registered through Neo's shop, Yoshi Mobile in Geylang Road.

Neo used the data of at least 78 customers who had purchased prepaid M1 SIM cards from him to register additional prepaid SIM cards without their knowledge, using data including their NRIC numbers, names and addresses.

He then sold the SIM cards to anonymous buyers who intended to use them to send text messages.

PDPC found Neo to have breached the Personal Data Protection Act.

The police also conducted investigations into possible cheating offences, as Neo was suspected of abusing the computer systems holding the customers' personal data in committing the offences.

If convicted of cheating by misuse of the computer systems, Neo can be jailed for up to three years, fined or both.

The offence of accessing a computer with intent to commit or facilitate committing an offence carries a jail term of up to 10 years, a fine of up to $50,000 or both.