Unresolved Optical Defect And Warranty Failure On Viewsonic PX749-4K

I am writing to report a serious and unresolved optical defect with my ViewSonic PX749-4K projector, purchased from Hepsiburada in Istanbul, Türkiye, from the seller Proof Teknoloji. Since early September, the projector has been suffering from a major image quality problem that cannot be explained by settings, usage, or environment. After the device warms up, black levels deteriorate heavily, areas that should be black turn gray, and there is strong light leakage from the edges. Instead of behaving like a DLP projector, the image resembles an old backlit LCD display with washed-out blacks and visible edge glow. Because of this issue, I sent the projector to KVK, the authorized service provider, under registration number 2502617884. Although a minor fan noise was addressed, the main optical defect was not resolved. After approximately 10 minutes of operation, once the projector reaches normal operating temperature, the image quality degrades again. Even when using reference test content such as the IMAX intro, areas that should be completely black show nearly the same brightness as the edge light leakage. Despite clearly documenting this behavior, the responses from ViewSonic Turkey and KVK were dismissive. I was told that this behavior is “normal” or that it “can occur around 800 lamp hours.” If the issue were truly lamp-related, I should have been contacted and offered a lamp replacement, which I was fully willing to approve, even at my own expense. No such offer or meaningful technical explanation was provided, and the device was returned to me twice in essentially the same faulty condition. I did not contact Hepsiburada or the seller initially, as I knew they would direct me to the authorized service. Instead, I contacted ViewSonic Turkey and KVK directly. This process has completely destroyed my trust in both. While there is a warranty on paper, in practice, when a serious defect occurs, there is no effective support. The problem is not properly diagnosed or repaired, but simply presented as “normal.” I expect this projector to be properly repaired so that black levels, contrast, and light leakage performance meet what is expected from a functioning PX749-4K DLP projector. If this is not possible, I request a replacement with a defect-free unit, evaluated under realistic operating conditions after warm-up.