DISSIDENT writer and editor Mr Li Guiren, released from prison on February 18, has written to his former employers demanding they pay for his living and medical expenses. Mr Li is bed-ridden and requires heart surgery and an operation for gall stones if he is to survive. ''He is seriously ill and can only walk three or four paces at a time. He is only 50 years old but looks about 70,'' said a recent visitor to Mr Li's home in Xian. Mr Li's family is virtually penniless however and can hardly afford the simplest medication let alone the expensive surgery he urgently needs. In a letter to the director of the Shaanxi People's Publishing House, Mr Li wrote that since he had never been formally dismissed from his post, the publishing house was legally responsible for covering his living and medical expenses. Mr Li claims in the letter, written just one week after his release, that since he had been ''illegally detained'' and had ''never admitted his guilt'', he was still legally entitled to welfare benefits from his work unit. The People's Publishing House had taken over his original employer, the Hua Ye Arts and Literature Publishing House while he was in prison, Mr Li said, and as such bore the responsibility for covering his expenses. The director of the publishing house, Mr Yang Xueyi, has yet to formally reply to Mr Li's letter but his wife Ms Fan Yunying has been told her husband's demands have been rejected. Despite this apparent set back, friends say Mr Li is determined to press his case and hopes to have a record of his time in prison published abroad. Mr Li was sentenced to five years in prison for ''inciting anti-government activities'', in May and June1989. A friend of former party general secretary Mr Hu Yaobang, Mr Li had taken part in the student demonstrations in Beijing that followed Mr Hu's death and organised three small demonstrations in Xian. Following the Beijing massacre of June 4, Mr Li unsuccessfully tried to organise a strike at the Hua Ye Publishing House to protest against the killings. He was detained at his office on June 26, 1989, but was not formally sentenced until after a second trial in July 1991. For the first two years of his confinement, Mr Li was not allowed any visits from his family.