A hosting provider has responded to my detailed abuse complaint with a request for additional information that our CDN doesn't capture:
Can you please provide us with exact source port number for all the addresses you have sent us. This is crucial, because this is the only way to find users in our system.
I suspect that they're deliberately trying to evade responsibility by making unrealistic demands.
Is their request reasonable? How can I handle this in a way that still holds them accountable?