REFUND REFUSED ON CANCELLED FLIGHT

I booked a flight direct wit SAA from PE to Durban at 06:55 on 11/09/2017. This flight was delayed and eventually cancelled and passengers transferred to the later SAA flight at 11:45. Since, due to my urgency to be in Durban, I had already booked three tickets on this later flight, I ended up double-booked on the same flight. The SAA assistant requested that I cancel the three later tickets as they urgently required seats for stranded passengers. He assured me that I would be refunded for these tickets. These later tickets were booked through Budgetair who are refusing a refund but SAA maintain that this is not their problem. I remain nearly R6000 out of pocket for something I did not need nor use. The plane, by the way, was full so they did indeed use my cancelled tickets to re-sell or re-allocate.