POOR service from VW - protracted Vehicle issue and failure to resolve

I have been experiencing some electrical issues with my VW Golf 7 TSI 2015 for the better part of a year. The vehicle is under warranty and yet the issue is persisting after continuously bringing it in to be rectified. This has been a terrible inconvenience and safety hazard to me and my family as it affects the door-contact sensor, auto hold (handbrake) and windows intermittently. Added to the constant back and forth as a result of VW Centurion's failure to address this issue, is the fact that they never have a courtesy vehicle available and this causes logistical problems for me and my family- this would not be an issue if it had been a once-off, but to be dealing with the same issue for such an extended period of time is shocking. Why and how is it that such a big brand (VW) is unable to resolve an issue with their own vehicle - I mean we are not dealing with bush mechanics here, are we? REPLACE THE PARTS ASSOCIATED WITH THE FAULT, what's the point of vehicle warranty???