As glad as Wu Cheng was to get a 2,000 yuan (HK$2,270) refund from the Guangzhou Haojin Vocational School, where he had sent his 15-year-old son to be cured of his internet addiction, he was even happier to get his boy out before the treatment got any worse. Mr Wu had stood in the hot summer sun for two days outside the closed campus after realising that the camp - which he initially thought was the best way to cure his son's addiction - was using methods akin to torture. 'If I had known my son would be beaten there, it would have been so stupid for me to pay money for that,' he said. Parents across the mainland are spending billions of yuan to send their children to newly established treatment centres, which claim to be able to cure internet addiction. But monitoring the methods of treatment has become a tricky question for parents, the authorities and experts from education, health, legal and other fields. Mr Wu, in his mid-40s, said his son had spent five to six hours a day playing games in internet cafes. He sent his son to the camp late last month for isolation. He and his wife, both migrant workers at small factories in Shenzhen, earn only about 3,000 yuan a month. He said that without support from his relatives, it would have been impossible for him to pay the two-month camp fee of 12,500 yuan. 'We work like hell in the factories because we want our children to learn more in school and behave better,' Mr Hu said. But after reading media reports that Haojin trainers were beating the youths, Mr Hu rushed to the campus in Nansha, a district of Guangzhou, to pull his son out. According to the contract Mu Hu signed with the Haojin centre, youngsters would have physical training, psychological consultation, and other courses. It said nothing about poor living conditions, the staff's frosty response to complaints and beatings. Parents were not permitted to see the dormitories and canteen when they visited, and Mr Hu said he was allowed to meet his son only on the playground or in staff offices when he came to pull his son out and ask for a refund on Sunday. 'All the youngsters were teenagers, and most of them I met said they had been beaten by the trainers,' Mr Hu said. A resident who had been inside the camp said there were neither air conditioners nor fans in the six- storey dormitory. The rooms had rusty window frames and some broken panes. The camp's director declined to comment. The Southern Metropolis News reported that educational, industrial and commercial, and propaganda authorities in Nansha district had closed Haojin and released all children in the camp. None of the officials would comment on the case. But the Haojin story is hardly unique. About 10 days ago, Deng Senshan, also a 15-year-old boy, was beaten to death at Qihang training camp in Nanning , Guangxi, where his parents sent him to be cured of his addiction. Police arrested 13 people at Qihang and shut down the camp after the incident. Another issue that arose last year in the treatment of internet addiction was the use of electroshock therapy. The Ministry of Health banned that technique last month. Kong Lingzhong - editor of Wangyinwang.com, which focuses on internet addiction research - said he was not surprised to see the problems spreading. A long-time observer of the internet addiction treatment industry, Mr Kong said that since treatment involved several aspects, such as education, health and psychology, the drawing up of standards and supervision involved more than one ministry. 'We need a new department to do that, or at least an official joint- working committee,' he said. Mr Kong estimated that there were about 200 to 300 institutes in the country treating internet addiction. He said the number had soared since 2005, when scholars returning from overseas introduced the concept of treatment. 'The industry grew very fast because of huge demand. That has also raised new questions for us,' he said. 'If just 1 per cent of those addicts needed treatment, it's still a huge demand.' An official survey conducted by the China Youth Internet Association, which is under the Communist Youth League, said in 2007 that nearly 8 million youths, of the more than 82 million young internet users, were addicts. Now, according to state media reports in June, that number could be more than 25 million.