failed to pay refund on Installment after trade in

I have trade in my car with Kia Randburg this year March 2020, they failed to settle my car. I have paid for the new car BMW installment and paid the installment for a car that I no longer have. Now its big struggle to get my refund being told stories when I ask about my refund, taken from pill to pill. Please never trade in your car with Kia Randburg, they don't settle once you have signed the contract for old