Payson Cha Mou-sing says allegations from fellow Asia Television shareholder Tsai Eng-meng - which he claims are unjustified - have broken his heart, even though he has already signed a deal to sell his share of the troubled broadcaster to a mainland tycoon. Cha was speaking a day after Tsai's company San Want Media Holdings filed a statement of claim in the Court of First Instance, accusing ATV directors Cha and his brother of breaching their fiduciary duty. Cha said he had signed a deal on Tuesday with Shenzhen property developer Wang Zheng, who had vowed to transform the loss-making TV station into Asia's CNN. He said Wang's investment had solved ATV's financial difficulties, and he was hoping ATV could rise as a great media platform in the region. But Tsai's lawsuit - which accuses the Cha brothers of backing the issue of new convertible bonds that can be exchanged for ATV shares at a price below the minimum previously agreed by shareholders - had turned things sour. 'ATV is my top priority, as it supports some 600 to 700 families. It was unfortunate that Tsai decided to sue me,' Cha said. 'It is heartbreaking and sad ... his claims were unreasonable and unjust. [It] is bad for ATV.' He said many decisions were executed only after obtaining Tsai's consent, and though he had been keeping a low profile, he had decided to keep fighting because Tsai had now 'gone too far'. Cha said the deal with Wang would be completed upon obtaining approval from the Broadcasting Authority, as required by the Broadcasting Ordinance. He did not disclose details except to say that Wang's influence on the broadcaster would replace his own. Wang, chairman of Shenzhen-listed property developer Rongfeng Holding, said he aimed to turn ATV into Asia's CNN, and he hoped that a year after the changes of ownership, ATV could be listed in Shanghai. Wang said his investment in ATV would come from his own pocket, and he planned to invest more than HK$2 billion over 20 years. Currently, Antenna controls 47.58 per cent of shares in ATV. Cha's family owns 51 per cent of the A shares of Antenna, which have voting rights, while Tsai owns the rest. Cha's family also owns 10.75 per cent of ATV's shares through Panfair. The rest of the shares are controlled by two companies, China Light and Dragon Viceroy. Cha and his family have injected HK$321 million into ATV since 2007; Tsai has contributed HK$274 million since he acquired his stake in March last year. ATV's public relations vice-president, Ip Ka-po, said the arrival of a new investor had yet to make any impact on production plans.