Took Toyota car in to just have the oil changed, T...

Took Toyota car in to just have the oil changed, Their was nothing wrong with car. went back to service and I was informed the brakes needed replaced and the power steering fluid was leaking and in need replacement. I have not had to add fluid since I have owned the car so I refused service for brakes and power steering got the car back in my possession, was driving out of the dealership when all the warning lights on the dash lite up returned to service department and they told me an O2 sensor was bad at the tune of 300.00. I am a mechanic but not from Seattle and I believe they broke this part to make more money. Read the reviews. This has happened to many people. I wish I had read them before taking my car to them. I tried contacting the service manager and to this day still have not gotten a return call