LG refrigerator freezing food

mark_elliot thought this was worth mentioning said

I noticed that lately food has started to freeze in my fridge. model LG LSX26366S . I tried to twist the thermostat, apparently it does’t work, since the temperature does’t change. Question: can I replace the thermostat myself (the warranty for the refrigerator has expired long ago) or is it better to invite a repair specialist. If the first option, then how to do it and which thermostat to buy?