If the fridge is getting to cold in there and items are starting to freezer this is usually down to a faulty NTC (temperature sensor). It will think the fridge isn't cold enough when it is so it gets it to cold and you get this fault.
To access the NTC this is in the air vent inside the fridge at the back at the top. You need to remove that and you will see the NTC. To replace this it needs to be cut off and the new one reconnected to it. They will come with the fitting kit on how its done.
Once that's been replaced it should then regulate the temperature in there and stop it from getting to cold and freezing things.