I've bought two brand new cars no problems in the ...

I've bought two brand new cars no problems in the past until I bought a used 2015 Chevy Cruze, in the last month I've had to replace a battery within the first two weeks, and I just replaced the brake pads on the car since they were down to sheet metal which I don't understand how it passed safety inspection, and I still have to replace the rotors since I can hear it. And the mechanics never made any recommendations about it except for the battery when I took it in for wheel rebalancing. I understand it's a used car but these above issues should have been looked over before putting the car up for sale and I've had problems first hand with used cars before from small private dealerships but I expected better from a big name Chevy dealership.