Bad After Sales Support/ Service.

Renault Duster recently purchased has already been booken in twice for the same issue i.e loud irritating noise on pull up/ Lower speed. 1st Booking : No fault found & asked to collect the car & record the noise( It was intermittent) 2nd Booking: The sound was recorded & sent to Duncan the sales person, Test drove the car with Duncan upon collection to get it booked in and he heard the noise.WorkShop Results: Was told they suspect contaminated fuel but I *******ed that becuase I use reputable filling stations ( Supporting info available). I was then told that a specialist has driven the car and says thats how those models sound which is *******. My Collegue drives the same with a K9K engine and emits normal diesel fueled noise and not this nonsense. Duncan is an exceptional sales person but what I noticed is that he does not have powers on workshop mattters which will the put his work and Brand in Jeopardy. Guys Im a technical and logical person and can differentiate between a normal & abnormal sounds. I want this car sorted because I have to listen to it everyday and also have more years to pay off this car. Duncan I am still waiting for the workshop report on what was done. Please take me serious because Im not letting this one slide.