Airline does not support tourism - just takes

I am a tour operator and I booked ten people on a flight from OR Tambo to Cape Town to see the Flowers.<br> In my industry, most hotels will give you a free room if you bring ten customers and other incentives. Kulula offers nothing. No benefit for bringing them business above the norm. Secondly, I needed to extend the time period for two of my guests and I had to pay R442 per person to make the change. You would think that since I had given them ten flights they would waive that charge. No, it is all just take. Consequently I am taking another ten people to Cape Town a month later and am wondering if any of the airlines actually support tourism. I am going to put in an effort to see if I can find one at least.