Audi Service Confusion

Hi, I'd like to enquirer about the diagnosis fee of the vehicle. My Audi had a mech b/down and it was towed to Audi Northcliff, they did a diagnosis, I then asked for the service history and quotation to be sent to my warranty. The vehicle has had a thermostat and cooling failures before. I spoke to my Salesman at Audi East Rand that I'm not happy about paying for recurring issues, he suggested that I get the car back to him in East Rand so they can assist me but Sales Advisor Northcliff won't let it go until I pay the diagnosis fee as much as the claim was yet to go ahead. I'm confused and my vehicle is stuck there with the festive approaching. I bought the vehicle 3 months ago, took warranty cover, took car for service but I'm not getting the service I ask for in times of need.