There's something like 6000+ votes for what is a rather obscure movie.
It's certainly not a D-grade thing that belongs below a score of 5. I personally score it at about an 8, but a 7 would also be fair.
So. Somebody really hated the people who made it? Somebody didn't get paid? Somebody made a slur against somebody else? If I could be bothered I'd go hunt it up.
But that negative score is most definitely artificial.
This film is like an extended Black Mirror episode, and I don't just mean by that "It's SF and modern! Like that, um, .... mirror thingy!' No it IS actually like a Black Mirror episode, in content and atmosphere. Very much so.
It's not the most wonderful film ever made.
But let's say - It's better than M Night's 'Glass'. I know that's a low, low bar but I was surprised by how much I ended up enjoying that piece of silliness after hating everything that came before it. It's not as good as 'Arrival'. It's a country mile better than that load of excrement 'I Am Mother' that recently smeared-up our screens.
'The Call Up' has reasonable acting. A good concept - done before like everything in current SF but not done exactly this way before. Props and scenery are good enough. Denouement is a good one and the script earns it. And it's not boring, it keeps you watching.
It's actually a pretty good film, I have to say.