Complaint

I am very disappointed with Mazda (South Africa) I bought a car from Mazda pmb branch in 2019 then before I went for my second service the car started giving me problems, I reported the matter at Mazda Nps and they never fixed the car and now this car is still so unreliable as it just go off in the middle of the road and restarts its self. I don't know how to deal with this matter as I have reported it without getting any help