Refrigerator with cooling and ice buildup issues

Have been dealing with this issues since we bought this fridge years ago. The freezer can't freeze anything and the fridge can't keep anything cool. We have had to replace the fan, sensor of some kind and the heating element multiple times it'd work for a while and then start malfunction again. The technician basically said that we should send it back because it probably has some kind of manufacturing defect but we couldn't do that because we don't live in a country with consumer friendly laws and the fridge is no longer under warranty now. I couldn't find any info about this fridge online. I think its a country specific model not available anywhere else. All the info I have about it I got from the sticker on the back.

Refrigerator Model: Kenwood KRF-371NF (No Frost)

Climate Class: T

Electric Shock Protect Class: I

Rated Voltage: 220-240V~

Rated Frequency: 50Hz

Rated Power: 165W

Rated Current: 0.95A

Lamp Power: 2W

Refrigerant/Amount: R134a,105g

Total Rated Volume: 371L

Net Weight: 69kg

The sticker also has this diagram