A unit of debt-laden Chinese conglomerate HNA Group has been hit with a lawsuit by Deloitte Advisory (Hong Kong), which is suing for HK$4 million (US$515,952) in unpaid service fees, according to a court document seen by the South China Morning Post . Deloitte Advisory, a consultancy unit of “Big Four” international accounting firm Deloitte, submitted a writ on Friday to the Court of Instance at Hong Kong’s High Court against HNA Technology, formerly known as HNA Logistics Group, a Shanghai-based unit of the conglomerate. Deloitte Advisory did not provide details of the services provided, and only said the charges were related to an agreement made with HNA Technology on March 16, 2016. HNA Technology has 14 days to make the payment or contest the writ, or Deloitte Advisory might take further action against the company, the court document said. Deloitte declined to comment, while HNA Technology did not respond to an email seeking comment. HNA Group continues to be hammered by the coronavirus pandemic. Its core aviation portfolio has been hit hard, with air traffic falling by more than 90 per cent globally in the past few months. Last week, Panama-based shipper China Joy Shipping filed a wind-up petition against the company . A trial will be held in Hong Kong on August 26, according to records available on the Hong Kong Judiciary’s website. This is the second time China Joy has filed for liquidation at HNA Group, the first instance coming after a debt default in 2012. HNA Group, which began as a regional airline based in Haikou, the capital of China’s southern Hainan province, went on a global shopping spree between 2015 and 2017 – mostly fuelled by loans. At its peak, it owned stakes in Deutsche Bank, Hilton hotels, a portfolio of office towers and real estate all over the world, as well as prime waterfront land in Hong Kong. After Chinese regulators started cracking down on its debt-fuelled acquisitions, HNA Group turned into a net seller of assets, cutting its debt by 40 per cent to 525.6 billion yuan (US$73.64 billion) as of June 2019. Hong Kong Airlines , which is 29 per cent owned by HNA Group, is in talks with potential buyers including Air China and Wuxi Communications Industry Group for a lifeline, according to sources familiar with the matter. The company recently completed the sale of a 20-storey office tower in Shanghai to a state-backed bad-debt manager for 3.6 billion yuan. It also stands to lose its overseas aviation portfolio, which includes Switzerland-based airport cargo handling company Swissport and the recently collapsed Virgin Australia.