Well if they are a "Major" sponsor they are probably on this board and reading this anyway, in which case their "friends at google" will turn up outside your house and skullfuck you.
Name and shame!
Honestly, what a load of shit. I don't think anyone can tell you how to place ads on your site as long as you are displaying the correct ads for the right content that is as much as anyone is expected to do.
Tell them to