Cancelled Flight Reference SHJGIY

I booked flights for 4 people from CPT - JHB to meet a client on 8 April 2015. Unfortunately 1 of them slipped his disc over the weekend. I contacted Kulula on Tuesday as the Monday was a holiday stating that the person was seeing a Neuro Surgeon in the morning and Im sure he will not be able to make the flight as he could not sit , drive and had difficulty walking. I was then told to wait and see what the Neuro Surgeon had to say. Needless to say after many calls I was told that I could change his ticket for another date. I asked for a refund but that was never accepted only to be told to change the date. I explained that I dont have another date as he is unable to make any decision about travel. Kulula was not interested in helping except for changing his ticket which I had to do that day.. I sent a doctors certificate stating that he was unable to fly but have had no response. The person subsequently had an operation. I think you need to have a death certificate before they refund.