Car Impound by Traffic Officers

Yesterday my son was stopped by a traffic officer and he took his driver's license and car disc and asked him to follow him where they lock up impounded cars and wrote two tickets for him, 1. for public transportation without permit, 2. For danger and obstruction of the road. We had to pay R2 226.00 to get the car back and also pay the total amount of R1 200.00 for the 1st ticket and the other amount we will pay later. My question is, can the officer take the car disk and the driver's license of a person and make them follow them until the place where they impound cars? How does one impound someone for public transportation in Polo Sedan when they are alone in the car. My son used to drive Uber and the car has double disk but at that moment he was waiting for me outside the hospital and there was no parking, and He was inside the car with the ignition on. We still use the car for personal use, does this mean the car has to be impounded every time my son is using it just because it is registered on Uber? When I tried to reason with them they said I will explain at the court, when I got to the court they said only next year 13 January in the meantime they are keeping the car or I should pay the fine. Please advice