Westinghouse Fridge problem. Hi i have a three door westinghouse fridge which has been working

Question

Hi i have a three door westinghouse fridge which has been working fine all these years but recently i experienced a wierd problem where the freezer as well as the centre section which works both as a fridge & a freezer are working fine but the lower fridge has just stopped cooling. It is just suprising how this has happened. Could u guide me in this. Thanks a ton. Rohit