No value for money on Renault vehicles. Vehicle under warranty with a dealership for 3months no solution.Escalation to RenaultSA fruitless exercise

My car has been stuck for about three months at the dealership Renault Mtata. RenaultSA remain non responsive and mischievous as they don't want to report to me in writing as well as the dealership. My car is under warranty but they have been misdiagnosing it and would not even get me a courtesy vehicle I'm paying instalments and have no vehicle. The level of professionalism is beyond comprehension