My wife and I just traded in a Prius for the 2015 Prius v (lowercase v for the Prius v wagon) specifically so we could get "more comfort" and enjoy the touch screen. The touch screen has been a problem since the first week. We've not got almost 7000 miles on it and have had two problems. The glove compartment latch broke around 5000 miles and a new one is ordered and the screen has been a problems from the beginning. A new one has been ordered to be installed whenever it arrives. We share all of your pain. I don't expect this kind of a problem with a new "high tech" car.
Seems to be a known problem on the 2015 Prius v. Here is the biggest thread on the subject if you want to read about the collective pain; Prius v (lowercase v) Touch Screen | PriusChat It can be a problem on every 2015 Prius v or the tread would be longer. So a bad batch of head units I'm guessing. Seems to be fixed by replacing the head unit. Sorry about disappointment, but I hope it gets fixed fast and you enjoy driving (in) your Prius v.