Hey, I am in the same boat. Bought my Samsung KS8000 Model in November 2016 and around 2.5 years later having vertical lines all over my 55" screen - not able to see anything. To be honest I don´t have time to deal with Samsung customer / repair service after using google / youtube and this forum about the same issue. I am also very dissapointed by Samsung, especially since most of my electronic items are from Samsung (2 cellphones, tablets, etc...).
I'm curious if there's already a lawsuit I can participate in. The TV was just too expensive to just throw it away. With all the complaints something has to be done. If not, then Samsung will definitely lose many customers and I am one of them. At the moment I still live in the States, but I will move to Europe soon. Customers definitely need to be warned. Also companies like BestBuy, Walmart, Costco, BJ´s, Target, etc... should react to customer complaints and not sell these products until there is an official recall program from Samsung to address this issue.