Damaged Russell Hobbs fridge

My mom bought a fridge from Lewis in Nov/Dec 2013 - since early 2015, she has been having problems with the fridge. The settings are no longer working properly - the top of the fridge is the most problematic. The food freezes or it does not keep the food cool, it feels warm and this is a waste of food as she constantly has to throw away food. She has on several occasions made contact to advise of the problem and she is being sent from pillar to post - she has been waiting for their technician to fix the fridge and its either they dont pitch up or if they do, they tell her they will come back. She has been to the store on many occasions as well but of no assistance. Now they told her they are waiting for parts for the fridge to be repaired. This is not her problem, she is still paying for the fridge without any delays and she expects the same from them. Lewis Store welcomes you home but it does not feel like home, it only applies when they want you to buy stuff from them. They must fix the fridge or replace it.