Samsung QE55S90CATXTK Sound But No Picture - Service Delay

I own a Samsung QE55S90CATXTK SS5 television in Istanbul Ümraniye. About 5 days ago, the device started having a serious problem: there is sound but no picture on the screen, so we cannot use the TV properly. After the problem occurred, we contacted Samsung customer service. They told us that they would come, but no one has contacted us or visited us since then, and the process is not progressing in any way. The lack of feedback and delay in service for a product in this condition is creating serious inconvenience. I request that a technical team be sent to check the device as soon as possible and that the necessary repair be carried out under appropriate conditions, or, if repair is not possible or economical, that the TV be replaced. I kindly ask you to urgently contact me, resolve this problem without any further delay, and inform me clearly about the process.