I've worked in that area. It was broken back in the 90s and I doubt the crusty old parts of the system have gotten any better. I was tasked with writing a more modern wrapper for part of the legacy system, and when I asked for documentation I was told they had literally nothing to give me.

I was just an intern at the time so maybe someone with more clout could have gotten sometime to dig in a forgotten closet for old technical docs, but it still strikes me as a very bad sign when technical docs for a system every agent uses all day every day aren't immediately available on the company's intranet.