Faulty vehicle knowingly sold to me

Hello everyone. I bought a Demo 2021 Renault Duster 1.5 DCI TechRoad on the 29th of October 2021 from the Renault Dealership in Port Elizabeth. The vehicle has 18400km on the clock. The very first day of taking ownership I had a complaint. The headlights were faulty. The following day on the 30th October 2021 the service spanner came on. On October 31 2021, 3days of driving the car the engine management light and service spanner came on warning me of a problem with the injectors and pollution system of the vehicle. I returned the vehicle after the long weekend on the 2nd November 2021 and was told they would attend to my complaint to which the response was that they are aware of the problem because it did the same while it was being driven as a demo model by one of their employees. This means I was misled and misinformed about the vehicle sold to me. On 3 November I went back to the dealership and returned the vehicle and asked for a courtesy vehicle since I was stranded. On 4 November I Returned the courtesy vehicle and spare key of the Renault duster which the dealership accepted. I proceeded to ask the sales who I could speak to regarding cancelation of the deal and the response was I should go talk to the bank who financed me. Today on 8 November I went to speak to the sales manager and was shocked at his attitude saying there is nothing he can do. I have not been contacted by the sales department following the purchase of the vehicle and today on my visit to the dealership I was told by the sales manager that as much as the Consumer Act is on my side it is also on the side of the dealer. I am appalled at the poor after sales service and treatment I ha e received. I have lost all respect for the Renault brand and have not faith in their product. I am now engaging with the Ombudsman resolve my matter

Curtis