i bought a brand new iMac Apple Retina MK462z/A i5, 27", 8GB, 1TB with S/N: C02RH13TGG7J . In the first week, before the machine completely shut down, the screen was making some vertical lines. Day by day, the signs were more often and a black screen was displaying while the machine was in ON state. Also, the fan was making noise. I sent the machine to a local Apple Authorized Service Center "Infoquest". They informed me that the graphics card was damaged. As the machine was under warranty, they replaced the logic board with a brand new on 15/09/2017. On July 2019, the signs came back. The fan started making noise again and very soon the machine's screen became totally black just after the boot screen (the white screen with the apple). Obviously, the graphics card became damaged again. But this time, the machine is out of warranty. As my job is Graphic designer, i bought an Apple iMac because i was feeling safe of the quality, support and performance of your products. After the first contact with the local Apple Authorized Service Centers in Greece, they disappointed me because they say that the machine is out of warranty. My family and friends that own at least one Apple device were pushing me to contact you in order to investigate my case and find a solution. My case makes me feel really unsafe about any future purchase of apple product.