A recruitment agency that helped to hire workers for a Hello Kitty exhibition last month is suing the event organiser for more than $10,000 for not honouring a "service fee".

The HR Ecology claims that the organiser, toy manufacturer and events company Mighty Eight, owes it money for the services it provided in coordinating the hiring of about 70 employees for the Robot Kitty exhibition at the Suntec Singapore Convention and Exhibition Centre held from June 11 to 21.

Mighty Eight also allegedly owes exhibition staff wages amounting to $50,000, said The HR Ecology.

The HR Ecology manager Jacqueline Neo said her company felt something was amiss when Mighty Eight became uncontactable around the payment deadline in the middle of this month. She said: "They were supposed to pay us but they weren't answering calls. They were also supposed to pay the contracted workers on July 22."

Last weekend, she went to a warehouse sale held by Mighty Eight in MacPherson, with colleagues and more than 20 unpaid exhibition workers.

There, Mighty Eight owner Jacky Teo was selling Hello Kitty merchandise from the Robot Kitty exhibition and his previous carnival held last year.

Ms Neo said they confronted him.

She said: "He wasn't picking up all our calls. So we headed down to the event to speak with him. He claimed that he is unable to pay us as he owes other creditors money."

At least one has filed a claim with the Small Claims Tribunals. Police reports have also been made.

Lawyers said their course of redress is limited. The workers' claims are not covered under the Employment Act as the contract signed by staff was a "contract for service" and a client-contractor type of relationship.

The Employment Act spells out the minimum terms and conditions of employment in Singapore. Those covered by the Employment Act can lodge claims of outstanding salary against an employer.

One unpaid exhibition worker, undergraduate Emily Chong, 21, who did not want to say how much she was owed, said she was disappointed by the company's lack of integrity. She said: "I'm quite disappointed as I kept my word and completed the work for the entire period I'd committed to but the company didn't honour its word."

Mr Teo did not respond to queries from The Straits Times.

The HR Ecology said that it conducted a background check on Mighty Eight before working with it.

This included checking its business profile on the Accounting and Corporate Regulatory Authority (Acra) database and verifying that it had a licence from Japan company Sanrio to conduct the Hello Kitty event.

Mighty Eight's business profile on Acra shows that it was incorporated in 2014 and registered to a Singaporean named Teo Choon Leng. His paid-up capital was $500,000.

The company's 2015 Hello Kitty event did not go smoothly either.

Fans were upset that a limited-edition paper figurine of the Sanrio icon was missing from an SG50 exclusive pack. Some had demanded full refunds.