2010 Ford Focus brakes Help?!

I got a used 2010 Ford Focus that had 34,000 miles. They said they got in a minor car accident but it didn't affect the car's function. When I first test drove it, it had squeaky brakes so I told the dealership that and they turned the roders. After I test drove it again the squeakiness stopped and I had no problems. I bought the car and it's been driving just fine. The other day I was parked down hill. I turned on my car and it started rolling so I pressed the brake pedal and it wouldn't go down it was stuck. I end up hitting a tiny poll that bent my wheel and the side of the car. I turn on and off the car two times and the brakes work now. I still need to get it checked out but now my car is messed up. I don't know why my brake pedal suddenly stopped working but now that it works I can't take it back to the dealer and ask them to fix it cuz it goes down now. I don't cant drive the car cuz the wheel is bent. Does anyone know why the brake pedal suddenly got jammed?

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