A HAWKER claimed yesterday he did not show up for his trial last year because he had been grabbed by Chinese police at the border and detained for eight months. Cheung Chi-hung, 36, contended he did not voluntarily leave Hongkong and, until he had been ''unceremoniously dumped back on the Hongkong police'', had been unable to contact anyone. He was deported from China in January and subsequently pleaded guilty before a magistrate to a charge of possession of dangerous drugs for trafficking and was committed to the High Court for sentence. Imposing an eight-year jail term, Deputy Judge Pang said Cheung, as a drug addict, should have known the serious consequences of assisting someone to store drugs. However, he noted that Cheung's right arm had become permanently disabled seven years earlier and life had not been fair to him. He also accepted the non-appearance at the trial was not his fault. Crown Counsel Wayne Moultrie told the court that Cheung was arrested after police found 166 grams of heroin mixture in his Ta Kwu Ling home in September 1991. He was allowed bail but failed to show up at his trial and a warrant was issued for his arrest. His counsel, Anthony Mitchell-Heggs, in mitigation submitted that when Cheung was working as a security guard his right arm was injured in the line of duty. He also suffered from headaches and, for this and other medical reasons, he resorted to taking heroin to relieve the pain.