It would help to post the make and model of your fridge.
However, without that my advice
is to first leave the door open and let it warm up inside for a day or two, meticulously clean the fridge in and out especially the compressor
, heat exchanger
, evaporator/plates, and any air passages associated with them. If you have a fan associated with your fridge make sure you also clean off the blades of the fan and that the fan motor
Once you do all that, turn it on and see if it magically starts working again. If it doesn't, you can start posting
the particulars on your system and move forward from there.