2017 Buick Regal

I was driving on the interstate going up the mountain and my 2017 Regal started to choke going up the incline. I was pressing my gas to the floor and nothing when this happened I quickly pulled off to the side when I tapped my brakes they felt as if I was pressing on a concrete block. I was able to stop but it was pretty scary. I had no cell phone reception going up this mountain in the dark late at night, I had to slowly drive the car home which was a good 20 minutes to go. Turns out according to my dad my brake vacuum pump busted apart so he replaced the part, he bought a GM certified part. This happened again just this past week it’s been a month and a half since the first incident. I had to spend $600 on the same part and I took it to the dealership this time. The mechanic said the part I had gotten must’ve been a faulty part he couldn’t see what the issue was and why it again for the 2nd time going up the same mountain pretty much at the same spot it happened the first time. The only difference was this time I had no other issues happening I was using cruise control hardly used my brakes the entire trip when I pulled off the exit I tapped my brakes and again it was like I was pressing on concrete. Seems odd that this happened so close together. I’ve had a lot of issues with this car once it hit 100k in miles. Electrical issues, just weird random things happen briefly and then it’s fine.