Bad customer service

Bought two vehicle's from Kia in Diep River in August 2020. This was cash transactions. To date I am still trying to get the vehicle's registered. Every 21 day's I must remind them that my temporary licence is about to expire. I am sure if I bought these vehicle's on HP these vehicles would have been licensed by now. No one at the dealership seems to be interested in the fact that it is already 4 months down the line and I can not go away for longer than 3 weeks before the temporary license expires again.

I contacted KIA South Africa via Email, but no joy from them either. They did not even bother to answer my mail.

What is my next step pse?