Hi,
Fly do provide support but (understandably) they focus on their paid plans (Plan Pricing · Fly). Customers on those will get priority:
Pro Plan: “Email support with guaranteed response times”
Scale Plan: “… includes a special email address for emergency support”
People from Fly do regularly respond on this forum. But for Enterprise-level usage, it sounds like you would be likely to pick one of those paid plans and so be less likely to need it.