This is one of those circumstances where being proactive will help rather than banging your head against a brick wall.
FWIW, a former sim buddy did as I’m going to describe.
First of all make sure you know exactly what you need.
Secondly, make the mental and emotional leap that this is all worth the time and effort it is going to take.
Lastly, forget sending emails, iron a shirt and get face to face with whomever you need to get the documentation from, it might take a week, or two days, but remember its worth the effort.
A perfect example of a bit of persistence happened when my mate was given the brush off by a person in fleet, it was resolved when he spoke face to face with a certain DSVP, the document was forwarded 2 minutes later.
This is an exercise in your interpersonal skills as much as anything else, it always helps if you start the discussion with “please, can you help me” as this works far better that the in your face of “give me what I need” even though that’s how frustrating it can be.
It will all work out and be worth the effort.