Flight cancellation issues when you have paid for additional policy to assist

Purchased tickets for early last month travel to Johannesburg. Admit that I didnt cancel my flight on the Monday going there because I fell ill, so I missed the flight and no refunds, however sent a mail on the same Wednesday I was supposed to fly back from Johannesburg to Cape Town later that evening, and no response from them except te automated response. If you try and phone their call centre you cant get through to a person. Why do you pay for additional insurance to be able to cancel the flight, but then you land up not getting anything right. Flysafair, you are absolutely useless.