Are Samsung TV's all that they are cracked up to be in South Africa?

We bought a Samsun UHD TV 4K on 21 March 2016 from a reputable dealer which was installed by them and all went well until last week, 4 weeks after the 2 year warranty fell away. We are now experiencing vertical lines taking over the whole screen. The dealer hasn't experienced this problem before so put us on to the local Samsung technician who came out and also hadn't experienced these vertical lines previously. Even after the technician dealt with what he thought might be the problem, electricity surge, the problem at a cost of over R2,500.00, still continues. We have been assured that there is not damaged to this television. Can anyone at Samsung give us a clue as to what is causing this problem please and what should be done? To have paid R24,000.00 only 2 years ago for this television seems to be excessive if this equipment is only to last the Warranty period. Not good enough Samsung! Is anyone out there able to assist please.