A man who prevented his girlfriend from returning a debit card she had found went on a $1,000 spending spree with the plastic and then threatened to release their sex video to deter her from reporting him.

Thomas Chua Poh Heng, 40, was sentenced to 18 months' jail yesterday, after pleading guilty to one charge of criminal intimidation, two of cheating and one of dishonest misappropriation.

He also admitted to two other counts of theft, which were committed in separate shoplifting incidents. A further eight charges were taken into consideration during sentencing.

The court heard that Chua's girlfriend had found a debit card in an ATM at Vista Point Shopping Centre on April 26 last year. She had intended to return it to the bank but when she told Chua what had happened, he took the card. He told her the card could be used, said Deputy Public Prosecutor Huang Jiahui.

Later that night, Chua bought liquor at two pubs, racking up charges of about $1,070 on the card. It is not known from court documents if his girlfriend was with him during these transactions.

The next day, he warned her not to report him. He sent her messages such as "If you report or leak anything about me, I will make sure you will be super famous, even more than a porn star", said DPP Huang.

He then sent her a video of the two of them having sex.The video was made a few days earlier with the consent of his girlfriend.

His girlfriend lodged a police report on the night she received the WhatsApp messages.

In separate incidents, Chua was caught shoplifting at Mustafa Centre in June last year and at Spa Bsfit at Festive Hotel on Sentosa in December last year.

Chua could have been fined and jailed up to 10 years for each count of cheating and dishonestly inducing a delivery of property.