we can't do anything to list this justwatch uses our data to list the available streaming services, I don't know if they support viki.com, you have to ask them

JustWatch lists the show correctly, https://www.justwatch.com/us/tv-show/heard-it-through-the-grapevine

So what's your problem with it?

Sorry, I should've been categorical - At the time of my response - the Data shows correctly in the JUST WATCH Website - however it does not show at all in the TMDB Website. Just saying there is a disconnect or a lag. You do not have to worry about it - I just wanted to point it out on this forum.