Does the line appear on all sources?
I bought a Samsung UE55ES6800 Tv in April 2013. It recently developed a white line across the screen about 8 inches from the bottom. Contacted Samsung and was told to take it to one of their approved repairers which i did. Was told it needed a new screen at a cost of £796 and they would contact Samsung to see if i could get a goodwill contribution. After 4 days i was told due to the age of Tv, Samsung were unwilling to help. After a few emails to Samsung to complain that a £1200 Tv should last more than 2 years i was told That it comes with a 12 month warrenty and any faults after that was down to me.
I think That if anyone is going to buy a Samsung Tv, They should look at getting an extended warrent because in my opinion they are poor quality and dont last.