Bosch Refrigerator, Spoilt Food, and Outstanding Issues

I purchased a Bosch refrigerator with a 7-year warranty. By the end of the third year, the lower compartment (not the freezer) stopped cooling, so I contacted Bosch Çankırı service. The technicians who came mentioned that the butterfly valve, which opens and closes to regulate cooling when the fridge door is shut, was not functioning properly. They said they would order the necessary part. However, without informing us, they left the butterfly valve permanently open. This meant that the temperature setting I adjusted had no effect whatsoever. As a result, goods worth over 2,000 liras froze and had to be discarded. Furthermore, when they visited on June 17 and promised to install the part by June 22 at the latest, I visited Bosch Çankırı service on June 22 to inquire about the status. They informed me that the part was still in transit and would be installed on June 23, Friday, if it arrived. On June 23, I visited again, and they casually informed me that the part had not arrived and would be installed on July 17. They wouldn't even have informed me if I hadn't visited them. All my meat and milk in the fridge went to waste. I have never encountered such poor service. When I expressed my concerns about the delay, especially considering the upcoming Eid al-Adha holiday, they dismissed me with nonchalant remarks like "Go to arbitration; we have 60 days." When I called customer service, I was met with uninterested responses, as if they were trying to brush me off. I cannot forgive the Bosch Çankırı service for treating my expensive refrigerator like a disposable item and their disrespectful attitude. My problem, including the damages incurred, still remains unresolved.