To be somewhat fair to Meta; the "violation of unclear rules part" part is an appropriate response for
spam detection.
Usually any entity dealing with the web don't want to reveal how their spam detector works because doing so could in turn reveal information on how to circumvent it[0].
The issue is that Meta thinks they're large enough that they can apply this to every single one of their business customers and all other parts of their policy as well - normally a company will be inclined to keep the businesses it's partnered with happy because losing their business can have a knock-on effect that could result in a bigger knock-on effect.
The sad thing is that Meta is probably correct in this assessment - losing one business wouldn't hurt them, regardless of spending. Even if you put a few thousand a month on the line, it's not worth for them to consider you. Heck even if you tell your friends about it - Meta doesn't give a shit.
The true Kafka-esque nightmare here though is that even just knowing someone at the company is apparently not even enough to get it properly checked out and fixed (even corporations like Google who have similar black box policies to most users have the means to do that). It seems Facebook runs on "computer says no" logic when it comes to cases they don't have data on anymore. That is truly disgusting.
[0]: This in part because most spam detection is ultimately still just checking heuristics; revealing the heuristic simply reveals what stat to adjust for. There's very few "sophisticated" detection methods - even the big email providers still just rely on heuristics combined with an internal trust score that they gain by checking how users respond to email.