Bosch Refrigerator KGN76AW30N/08 Cooling Failure

I have a Bosch refrigerator with the serial number KGN76AW30N/08. In early February 2024, we reached out for assistance with a cooling issue. They arrived, identified a problem with the thermostat, and installed a new one, but unfortunately, the issue remained unresolved. We reached out once more, and they proposed a potential problem with the circuit board, resulting in its replacement. However, the issue persisted. During another conversation, they mentioned that they would be taking the refrigerator to the workshop for a more thorough examination. They brought our fridge to the workshop in the third week of February 2024, and originally estimated that it would be there for approximately a month. However, it remained in the service for about 2.5 months without being returned. They said the fridge was fixed and returned it on May 9th, but the cooling issue still remains. Now, they're considering returning it to the workshop once more, suggesting that a compressor replacement may be necessary due to a non-user error. They mention that it's no longer covered by the warranty. Do these appliances have a limited lifespan of only seven years? Isn't it reasonable to expect someone to assume responsibility once the warranty has expired, especially if it has been extended? My family has been dedicated users of Bosch products for three decades, but we have been experiencing ongoing difficulties for several months due to a minor malfunction. I would like to speak with someone who has the authority to help us resolve our issue.