Bosch KGN76CIE0N Fridge Not Cooling Properly and No Response from Customer Service

My Bosch KGN76CIE0N 526 Litre XL NoFrost refrigerator is not cooling enough. The service team contacted me and placed a thermometer inside the fridge again, which was retrieved after 4 days. After the thermometer was collected, a woman from customer service called, stating that "There is no issue with your fridge; the cooling is normal." I replied that I could tell from the food inside the fridge that it is not cooling properly and that I still had the same concern. An hour later, a service technician from the Bosch service in Samsun, who placed the thermometer, called me and said, "As the measurements indicate, there is insufficient cooling in the fridge, and the defroster stays on for too long. If you agree, we will replace the motherboard and sensor." I responded by saying that I do not want the motherboard replaced in a fridge I bought just 5 months ago; I want the fridge replaced. He said customer service would call me, but I have not been contacted yet.