Engine Shut Off Without Warning problems of the 2017 Cadillac XT5

My 2017 Xt5 completely shutdown on my on Saturday, 10/7. I was at a stop light & when I pressed the accelerator, the instrument cluster had a number of lights come on & the vehicle was very hard to accelerate. I had to pull over immediately & then the car shut down. It was completely dead: the hazard lights did not work (very scary) & onstar and the sos button would not connect. After about 5-10 minutes, onstar was connected & I was told not to drive the vehicle due to engine & transmission codes. The vehicle was towed the dealer by roadside. On Monday, the dealer provided me with a loaner while the diagnosed the vehicle. On 10/11, when I went to pick-up the vehicle, I was told the issue was a 'logic lock,' the car was driven for 4 miles & considered fixed. I refused the car as we need to know the root cause. The dealer still has my car and has not contacted Cadillac yet. I am still waiting to hear from them and also have a case opened with Cadillac customer care, but they are less than helpful. The poor customer service is one issue, but the greater issue is the safety of my car and the fact that it completely died on me and the dealer thinks clearing some codes will resolve it. Please help. God forbid this happens to me or someone else again. It is completely unsafe.