2x for repairs and still not working

Bought a dual section wine fridge 3 years back. Vents were not working and the main board got replaced by the local (in Windhoek, Namibia) agent (after first getting it back as "apparently working"). Warrantee or Guarantee not applicable, as it was apparently not a compressor but a technical issue. Got the fridge back, set to 3 degrees for whites and 18 for red and that is also shown as current temperature on the display... However, checking the temperature with a thermometer, both sections are actually around 5 degrees (compressor nearly running constantly). Cold red wine, how nice. What to do, as I am actually sick and tired by the forth and back and still do not have working wine fridge. I would expect some more client-friendly solution for that, e.g. replacement or so.