Sorry to hear about this. The green line on your display can be caused by any number of issues, but is indicative of a hardware issue. Please bring your device to your nearest Samsung Service Center for diagnosis and repair.
Samsung already diagnosed my phone they said this usually happens during thr process of updating they recommend to swap my cp with corresponding discount but still the price is so expensive
What? If that is true nobody will update. That tech guy is just making an alibi to say something even not true. Nobody can say even the manufacturer of amoled screens the real cause of amoled burn. If samsung will learn what that tech is saying, pretty sure he will be reprimanded. The only truth in what he says is that you really need to replace your phone screen. If you didnt want to experience again this situation, buy phone with lcd display and be contented with low display quality.
They may have said that as the issue may have come from the ribbon connecting the screen to the motherboard. When updating, some devices tend to run a bit hot, which can cause things to stop working properly (such as the screen ribbon.) Contrary to what Bong_J_San_Pedro said, our Service Center technicians do not just give you excuses to get you to pay more - they do their best to provide you with the right care you need for your device.
Keep in mind: no matter how tough smartphones are built; the internals are still very much sensitive electronics that can fail due to any number of reasons. It's not that the engineering is bad - it's just even the best engineers can't predict everything that might happen to a phone's internals 😥
Sorry to hear about your experience, and that you find the swap a bit too expensive - but it is honestly the best-case scenario if you don't want to get your screen replaced right now.
