Don't worry about going for the head honcho as long as you are sure of your facts and are polite and constructive.
I had been messed around right royally for over 18 months, first because someone of the requiste rank was not in post, then they needed time to get in post, then the paperwork was lost, then it was paid (only it wasn't) and then it all started again and still nothing happened.
I went direct to a CS * equivalent at STC and got a charming thank you back. Job done.