Remember, to receive prompt support for failing Google services, you need to contact Google via a story at a famous blog, a major social news site, or (ideally) The New York Times.
I have been a paying GAFYD user for ~ two years and wasn't even aware there was an 'account PIN'! I fear for most people this simple solution may come with the benefit of hindsight.
> "Please note that for your security, your Customer PIN will be updated periodically.
So even if I find it now and write it down, there's a chance that I still won't be able to access support at some point down the road if/when I need it.