4k

Hello; Does anyone have this issue? When I previously tuned to a Fox channel, a screen flash would ask if I want to view in 4k. I clicked the button, and it would switch. Last month, I was sent a new Gemini Air device due to some other issue. Yesterday, I wanted to see College football on the 4k channel. I received an error message stating that "This Device Does not support 4k" I called DTV. They said that this a problem they working on. Is the the truth, or is it just to get me off the phone? Oh, and they can not send another device, because two is the limit! 

Thanx