jeep centurion what a service

i recently bought a car at Jeep Centurion and the service was okay , bought the car end of November but January had to service the car and i accepted that but now three months into driving the car and the car has funny sounds when you hit the brakes or a day after it rains there will be a pitch sound when you reverse not happy at all because they never mentioned to me that the car has a brakes system problem or something this was a day light robery.