This scenario would mean major negligence on their part, as they had been with Cloudflare for years. When it was clear their services were costing more than the business plan paid for, that's when they should have been contacted with clear numbers and a sheepish admission that "unlimited" doesn't actually mean unlimited. It certainly seems shady to me that they attempted to make it about a TOS violation, that there's no public information about enterprise level and pricing, and that the second they said they were talking to a competitor they had their data purged. It sounds like a failed attempt at extortion to me.