Non Refundable ticket @!!@!!@

Disappointed with Kulula Airlines, I booked my return flight a month ago to travel to Cape Town to help my dad move. Plans have changed movers are coming 3 days earlier and I am driving back with my dad. I'm still flying to Cape Town but no longer need to fly back. I called Kulula.com and was told they will not refund the return flight on the 29 March. This is ridiculous I'm giving them 10 days notice!!!! Plus this is over Easter they can resell my seat. I asked if I can sell the return fare to someone and change the name, they said no name changes are allowed! I think this is shocking Kulula, when I made the booking it does not say the flights are non refundable if I had known that I would have paid a bit more if it was FLEXIBLE and I had the option. Not happy!