Can anyone help me

I received my car back from garage after it had bumper work done. The outside temperature is now reading between 30-60 degrees. Any idea what has happened? How easy it is to repair? and how much it will cost?

Thankyou people

 

Wouldn't surprise me if they damaged the sensor or broke its holding bracket and ziptied it up against the radiator. That'd influence the readings. Pop out the center lower grille on the bumper - it's behind there. Should be on a small bracket on the core support, with the harness coming off the right side of it (as you look at it) and going toward the driver side.