A WOMAN who was jailed for five years for blackmailing her doctor yesterday failed to get her sentence reduced by the Court of Appeal. Sin Kam-fung, 31, was convicted by the District Court in November 1993 of blackmailing Dr Wong Po-chung and claiming to be a member of a triad society. Sin was treated for tuberculosis by Dr Wong at his clinic in Wuhu Street, Hunghom. The earlier court had heard that the blackmail took place after Sin borrowed $10,000 from Dr Wong but failed to repay him. After claiming to be a triad member, she subjected the doctor to a series of demands and she received payments totalling $30,000. The appeal, heard before Mr Justice Litton, Mr Justice Bokhary and Mr Justice Liu, was dismissed. She had received a proper sentence in view of her conduct.