I’ve been out of the support team for a while but we train all of our support staff in the fundamentals of every payment scheme we support and they should be able to answer the vast majority of questions we receive fairly quickly. They can also then take further training into a specialism to handle more in-depth investigations.
On top of that, we have a (fairly!) comprehensive set of internal documentation that anybody in the company can read.
In increasingly rare cases, this does fall short though and our support staff do have to go directly to an engineering or operational team to find the answer to a question and get it added to the documentation. It sounds like this was the case here.