Complain

I am Tebogo Tom Monyepao. I sold a car in 2019 to SMD. The license number of the car was still valid at the time. After several times when I pay the license disc of my other cars I get informed that the car is still mine whereas it was sold to SMD and I got paid. This is 3 year I cannot get license disk of my other cars because of this issue and the SMD does not want to resolve this matter. I also attached the document that still shows that the car belongs to me. This car is currently owing 3500.00 of the previous license after I sold it.