Hugene - 6:51 pm on May 13, 2010 (gmt 0)
Eurydice, saying publicly that "AdSense can be hacked" is no threat or news to anyone, we all know that.
I am not sure if I understand your situation or not, but I have a few advices for you:
1) Immediately remove all AdSense code from your sites: what's the point of serving these ads if you were hacked, and you don't get paid for it. Google will never believe your story that you were hacked if you keep serving these ads.
2) Make sure your never use the same password for your G account and any other account. Your G account should be protected like a bank account.
3) If you use Windows, re-install your machine fresh. If your with Linux, you're better off. I say re-install because you might have a key-stroke recorder installed on your machine by the thief.
4) After your machine is cleanly installed, or from another clean machine, preferably using a land-line Internet (not wifi), change all your password. Absolutely all, because chances are that if they got your G account password, they have all the other ones too.
5) Now contact Google again. If it really doesn't work, you might need to open a new account.
Basically, you need to sterilize all your online work environment. Once you're hacked, you can safely assume they have access to pretty much everything.