>>32214303generally it would fall under anticompetitive practices. If a big player trying to shut out competition, it is against the principles that keep the free market working, so there are laws in place that try to facilitate competition and protect weaker businesses from simply being crushed.
It also depends on how big the offender is, the market leader being anticompetitive is a lot more severe, than a nobody doing it.
But as said it's something that is hard to prove unless it's really big case (the bigger the whole thing, the more likely that someone fucked up in some way). In theory you could also just collectively claim that "competitor being canceled" is unrelated to whatever you discussed with the host.
But it's fairly complicated and lots of criteria come into play.