bad apple

I have purchased two cars from we buy cars , service at their Cape Town branch was good . The second car a kia Sorrento has not driven more than a few KM's since purchase . I cannot even get the car to road worthy as it does not run . I have already spent thousands on repairs and have now been quoted 58k from kia to get the car running . I purchased the car 4 months ago and want a refund or credit .....head office not responding to my email . This is unacceptable , the car does not run