1. TV is at http://www.samsung.com/us/televisions-home-theater/tvs/4k-uhd-tvs/58--class-mu6100-4k-uhd-tv-un58mu6100fxza/#specs
I see the usual optical out and ARC. ARC is always hit or miss so we never count on it.
2. Let's check the other thing.
https://www.manualslib.com/manual/634195/Yamaha-Htr-2064.html?page=6#manual does not show HDMI 4K support. Could be why they said no.
https://www.manualslib.com/manual/634195/Yamaha-Htr-2064.html?page=16#manual shows it does have optical connection so you could run optical out from the TV but BEWARE that Samsung almost never passes more than Stereo if the source is HDMI.
So my bet is they are right.
https://www.google.ca/search?rlz=1C1GCEA_enUS762US762&q=Yamha+HTR-2064+Home+theater+4k+support&oq=Yamha+HTR-2064+Home+theater+4k+support&gs_l=psy-ab.3...3049.6655.0.6722.214.171.124.0.0.0.134.942.9j2.11.0....0...1.1.64.psy-ab..0.8.673...0i8i13i30k1j33i160k1j33i21k1.0._wMt_gDam8U did not find this model with 4K HDMI support.
I have recently purchased Samsung MU6100 TV 55 inches. I called a technician to set it up with Yamha HTR-2064 home theater, he told me that this TV is not compatible with Yamha HTR-2064 Home Theater. I am not convinced on this. Can someone guide me about the correct method to do it