Always always keep control over your DNS. If this guy was hosting with Slicehost or Linode, he would've had the option to point the MMX records anywhere he liked, and problem solved (or at least, temporarily contained.)
Lastly, I can say from personal experience that Google's support is shockingly bad. It is a deep and twisted warren of blind alleys, misinformation, and a million different paths that all end in "fuck you". You will not contact a human. There are no humans. Thousands of genius engineers engineered teh googelz to be perfect and human free for your utopian pleasure, and then they spent all day riding around on bikes and playing ping pong and eating free food and getting massages and inventing world-changing things. They're better than you. Google doesn't have problems. Ever. You must have done something wrong.
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Their approach to customer service is to send their customers in circles until they give up. It's evil. Very extremely cruel and evil.
I use google apps for two of my domains. What can I say, their software is very well designed, and on the net balance, it's easier to manage than postfix. But the lack of support is a major down side, certainly. I wouldn't even consider paying a dime for any of their services without seeing some huge changes in their approach.
Mind you, we have a fairly esoteric mail forwarding setup, but still one that their support documents describe as possible.
Haing said that I've been happy with how Gmail has been compared to a traditional UNIX-based setup in administration and would not want any other email interface.