whats wrong with my fridge freezer?

Recently my fridge part of my fridge freezer has started turning off (the light inside light is also a bit iffy) and then a couple of days ago i noticed all the freezer stuff was defrosting as well as the fridge not feeling cold so thought that it had packed up totally (its only about 18 months old) so took my freezer stuff to my neighbours and now this morning found it the fridge is cold again and the left over stuff in the freezer has refrozen (this is now all for the bin), so now i dont know what to do, do i get a new one, try and fix this one or what lol. Any info would be greatly appreciated as i really dont want to have to buy anew one but dont want to give me and the kids food poisoning!!