Total incompetence

We sent our Hyundai H1 to Vereeniging Hyundai , under warranty, as the vehicles motor was knocking. They replaced the diesel filter, and charged us for it, as they say they only changed diesel filter after 60 000km. The problem was not fixed. We sent it back again the following week, still no joy, now they have to replace the injector but they dont have stock so \please bring it back next week"we were told. The vehicle has been there for another two weeks now and still no progress has been made. To top it all off"