Freezer ( malfunctioning) (Culgaith CA10)

Hoping someone can work with this otherwise it’s going to the tip. It suddenly defrosted before Christmas, only 5 years old and in pristine condition. Such a shame but can’t figure out what is wrong with it and the company we bought it from are not being helpful. Surely someone in the know could tinker with this?? Hate to dump it. Especially as it still seems to be functioning as a fridge but possibly not for much longer. Collect Culgaith.