In order to fix it, go to a nearby mobile store that has PROFESSIONALS and make sure you ON maintenance mode while giving the phone, they will check the display and probably switch the display, but if they say it cannot be fixed, then you go to Samsung and check, if they say it cannot be fixed, save all of your data in another device or transfer it, (first check with the shop you purchased from if you can refund) refund your empty phone and you will get 90% of the money you paid back (maybe not 90%) then you can purchase a new phone with the update installed and then transfer your data back into the new phone and Ta-da, no green line.
We would like to apologize about the frustrated case you're going through, and we truly understand your feelings. However, kindly note that Samsung doesn't support the international warranty. So, If you are willing to repair the phone in India the service will be chargeable. Also, Samsung's warranty covers only the manufactured defects within the warranty's period ( 1 year from the date of purchase), any other defects won't be covered under warranty, unfortunately. For more information about the warranty's policy please visit the link below. https://www.samsung.com/ae/support/warranty/