Daewoo american fridge freezer not cooling

hello

i have a daewoo american fridge freezer in black, it has water and ice dispensor, and recently the fridge has stopped being cold.

ive read numerous forums on the net and have tried many of the recommended fixes ie defrost for a few days etc make sure there are no blockages however none of these seem to do the trick.

all fans work the bottom vent into the fridge is clear as is the top one now im stuck as what to try next to get the fridge cooling again.

does anyione have any advice or recommendations on a possible solution to this.

thanks to anyone who can help in advance