Great brand poor service

I bought a Jaguar E Pace in 2018. My experience with servicing the vehicle seems that the service department doesn’t know everything about the vehicle. This week is the second time that we take the car in with a big issue and the computer tells the mechanic nothing is wrong with the car. The previous time the problem was only diagnosed after the warranty lapsed; yet no acknowledgment that they’ve been wrong all along long and it was a big issue: the car would switch off unannounced in traffic. This time the car lost power to the point of 70km/hr on the open road. Yet the computer says nothing was wrong at all. I’m imagining stuff, until the mechanics catch up with the problem. A great brand messed up by very poor service.