Paramount plus with showtime error

I can enter Paramount plus  with Showtime no problem . I can access paramount plus on other devices ( smart tv). When I try to use paramount plus but it doesn’t say with showtime, I get in, then I get an error screen, the screen disappears when the show starts, but returns a moment later. It stays up although you can hear and sort of see the show running in the background. I’ve tried all manner of resets both on my own and with several phone agents. They sent a tech out who basically refused to change out the box, saying it won’t make any difference and they would charge me for doing so. 
any ideas? I REALLY want to watch this channel that I am paying for!