Hotpoint mistral frost free ?

I have a similiar problem to that mentioned by others. My Fridge freezer went from a cool -22 and 4 degrees to -11 and 26 degrees in the frdige and still rising. I have put the Fast freeze on and managed to get the freezer down to -16 but the fridge is getting hotter. I have taken the front and back grills off and hoovered out. the fan on the left at the back appears to be working fine and the large blck thing - sorry don't know what is called on the right is very very hot. Cold air is being blown out of the front grill at the bottom on the right as you look at it but still problem not solved. I have seen mentions of fuses/bulbs etc but not really sure what these are so don't want to dismantle it any further without advice- can anyone help- just stocked up on food for christmas !!!!