repeatedly SHOCKING service for faulty new car!

Vehicle purchased from this dealership 7.2.2014. From beginning, vehicle made a high pitched whining sound as soon as I drove it over 100km/hr (in conjunction with certain angle of accelerator peddle).SATNAV/ Radio system problems from day 1-taking time to switch on etc(this has deteriorated,now,and 1 of the USB ports was always faulty. I have a busy business which takes up a large portion of my time, so I left it until Nov 2014 to bring the car in with the above complaints. I left the car there for the day, and when I returned, took one of the friendly engineers on the road to show him the high pitched sound issue. He assured me that someone would contact me to get the car back in, as this was a problem they needed to look at-not normal for a new car.I received no phone call/correspondence. March 2015 I tried again. Called service area,spoke to Kurt. Friday March 6th I brought the car-showed them same issues-was told car needed to me seen to and could be up to 3wks.thought it would be sorted. was told days later that they did not have a courtesy car!Was not contacted again.7 April 2015-manager Carl Cupido- brought car in AGAIN-showed issues.AND NO correspondence AGAIN! THIRD TIME!