INJURY On duty (Deceased)

Guys help me My Dad was a police Man and he died 2006 inside the government premises he got short serveral times and no case was opened, No IOD( Injury on Duty) nothing happened so I went last year to Mpumalanga police station (Hammarsdale) and thy can't help me till Today I always use my airtime to fone them bt thy dont do anything no follow up so please guys help me