Renault Tygervally

I have recently taken my car to Renault for an update. however, my car has been having endless problems ever since they gave it back to me. I have contacted the dealer principal but he only assisted with one issue. I have had this car only 8 months now without any issues before they started working on my car. I have made contacted with Renault SA customer care but their response is "We assisted you already" but my car is not functioning as it should.