Model ARB2259CS,Everything is freezen in fridge

you should send model number,if you have a damper control in your model most likely this is the problem,all that happens is cold air blows over from the freezer from the evaporator fan and blows through the top section of the fridge side,if the damper door isn't closing all the way it will cause freezing in the fridge section.

temperature sensor is not working
this part to control the temperature in the fridge

Hi
What is the model of your fridge.

On the older fridges, a faulty thermostat would cause the fridge compressor to run continuously and therefore, would not regulate the temperature.

On newer electronic models, you have temperature sensors giving signals to the control board. These can fail.
Ash

Check the fridge sensor. On my Hoover HNMF2805AL80 f/f, first I replaced control module - still freezing.
Have just replaced cheap fridge temperature sensor. Part No. 97061619. Trouble is you have to cut into insulation at back of fridge to replace. I just plugged in sensor & placed inside fridge at back at the bottom - so far so good, only lettuce freezing now, everything else v. cold but not frozen. :)

The fridge gets its cold air from the freezer through a vent(damper) between the freezer and fridge.The fan in the freezer blows air through it. Make sure this fan is running. You may have to hold the door switch in for it to run. There is a flap you adjust with the fridge temp. control. Make sure it's opening and closing when you adjust the fridge temp.
The problem could be the electronic control if you have one or the mechanical linkages.

If the fridge side is frozen you have a door seal issue.
If the freezer side is frozen you have a defrost component issue.
Your post was not clear as to which side is frozen.

Generally speaking, sounds like you may have the frozen condensor problem that is so common
because of the design flaw in the Samsung products.

Turn it off, empty the freezer.
Study the back and look for formed ice around the seams.

So it got too cold, and now it is still too cold, or not cold enough ?

Check the damper between the fridge and freezer. It may be broken or frozen open. If this happens and you have a water reservoir in the fridge then it could freeze and crack - leak and then flood your house... Shut off the water supply until you get the problem fixed.

the temperature controlis most likely bad since you cant control it. the control is the knob you turn to set the temp with. you should be able to replace it yourself fairly easily.

It is possible it has a bad thermostat but most likely cause would be a bad damper motor.  It is the vent inside the fridge that opens and closes, based on temp. setting, to allow cold air from the freezer into the fridge section.