2012 VW Jetta 2.5 SEL

I have a 2012 Jetta 2.5 SEL, approx. 34K miles and under warranty. In the last month, the car has begun to not start intermittently. Absolutely no power, no electronics, nothing. I can turn on the lights and lock and unlock the doors with the key fob but that is it. It starts like this, I press down on the break and then press the ignition start button and no response. The brake pedal then locks up. No indicator lights, no electric to windows, etc. After about 3-4 hours the car will start again normal, but within a few days this will repeat itself. My wife took the car in to VW and they said they inspected the car and found nothing wrong, when she got in the car to leave it was again not working. They’ve now had the car for over a week and had called a few times to say that they hadn’t found anything yet. Now this afternoon they called my wife and told her that there was ‘probably’ a coin got into the car a damaged a circuit and that any repairs would not be covered under warranty and that we should be thankful they’re not charging us for the ‘many hours’ they spent looking at our car. It took them a week to come up with this assumption – NOT fact. I will be going in to give the service manager a piece of my mind, but has anyone ever heard of anything similar to this? Did VW really design a car with a single fault failure like this in which a coin falling in a vent can completely disable the car’s entire electrical system which in my mind is a major safety concern?