Bad service

The kind of service we receive from the drivers when we have discounts is very bad. I had 50% off and I requested. A driver by the name Themba driving a kia rio with registration no HC78VZGP accepted my request once he realised that there is a discount he canceled the ride. I requested again, had to wait for more that 10 minutes and neaby drivers did not accept. 10 minutes of waiting for a driver to accept plus I had to wait for a driver who was 11 minutes away when they were drivers who were 3-6 minutes n refused my request. This is not the first time I come across such service when I have a discount but when it's expensive they are all available to accept my request. This kind of service is very unacceptable.