Unfair treatment

I bought a car from Audi Polokwane and I experience issues I reported to them aft they delivered the car and now car break down Audi Sandton repair it but not everything so Audi Polokwane want to give me another but they want me to pay for that car which I don't understand as they are going to keep it so I ask that they meet me half way as warrant only paying 5% so I must pay the remaining balance and I haven't had a car for 5 moths but still paying my monthly installment and the car was not even a year when it break down and before they agreed that they will meet me half way now they are changing saying that they don't have the car that they want to give me I must wait my question is for how long while we waiting what's going to happen to that car as I am paying every month and Audi Sandton need their money as the car is still by them