Insurance bogus

My father opened up a policy through Ackermans and in all the efforts to pay for papers from the hospital that cost us almost a R 1200 that's beside the traveling cost. Just telling us that the application was declined because my father wasn't cover for that natural causes isn't natural causes natural causes? We don't understand but I really want to do something about this because it was a small policy but however at the end of the day the up and down almost cost us half of such now which we do not get. What can we do