4 month old car with mechanical issues

I purchased my brand new Renault KWID Dynamic from Renault Highlands North . It makes a beeping sound when I drive over 70 km/h . I reported this to them firstly on 12 August , I took the car in to be told there was nothing wrong with it and was charged an assessment fee. I then reported it again and gave them proof as I had taken a recording of the sound and was then told they would arrange with Renault 24 as they suspected it was an alarm malfunction. I constantly need to chase for feedback regarding this matter, poor communication from the dealership. Disappointed first time buyer!