TV screen is flashing

This happened last night and I was able to get it fixed with a refresh. But it started up again. The refresh/resets have not worked. I was already on a call with a rep the day before who said she had sent a signal to the box and it would restart but it didn't come through. How is it I am able to remotely reset it but the rep cannot connect to the box? How can I stop the flickering? It is constant with black and the regular tv channels (all of them) and there is sound. I checked the cables and they are not loose.