samsung fridge freezer model srs 2028 cvw

My Samsung fridge feezer has a problem
the fridge part has a fan which keeps icing up and the ice then stops the fan from turning
when this happens the temperature in the fridge rises but the bottom of the fridge gets very cold and the water dispenser feezes up

does anyone know why it keeps forming ice around the fan ?

it was fine for the first 22 months and first iced up whilst still under manufacturers 2 year warranty the engineer came out and deiced it but it iced up again within a few months it has done it several times since and seems to be getting more frequent

warm beer is very uncool!

It's a known problem. You should have got them back out as it would have still been covered from the previous repair.
Normal thing is defrost system not working. However, the plenum chamber also needs to be replaced.
There's a whole host of things need doing to rectify the problem, sorry can't remember most of it and I no longer have the service bulletin.