To get your work done by this VIP, this last time you will need to come armed with the name of the chief executive officer of the company. Get that from the main switchboard operator. When the unavailable Very Important Person’s flunky starts to give you the runaround again, sternly tell the flunky something like this:
“I didn’t want to bring [use full name of the chief executive] into this little matter. I thought your [use name of very important person here] could handle this him/herself. I guess not. Well, I’m calling [first name of chief executive] for a luncheon soon, and I can just ask him/her about this matter then.”
No person wants the superior, especially the chief executive, to think that he/she is incapable of handling routine matters. Beyond that, the fact that you have namedropped adds a dimension few bureaucratic managers care to call as a bluff. It’s easier and cheaper to finally talk to you — and satisfy you.