Bad quality and no Service

Booked service call with Hisense for a faulty LED tv with LED clouding issues and pixelation. On the 09th Of October a technician from Mikectrolight Appliances services came and did nothing to the TV all he did he left 2 of my HDMI cables not connected.All he said he could not see the issue. I sent him visible pictures showing on Cartoon Network on white background there is LED clouding showing a patch of green. And on the logos and letters the picture looks scrabbled and bad .He said l must change HDMI cables. The following day l bought 2 HDMI high speed and tested the fault is still there took multiple pictures and sent him and also emailed Hisense and no one bothered to respond. Then Karabo Sanyane ask if l still get the say issue via USB or ext HDD. Advised that its still the same even when l screen mirror from a smart phone Samsung S7 edge. Up until today no one has done anything.