Sorry to hear that from you, so sad they did that. I use Adsense too, but so far nothing happen because i just very new to it, just about 2 month. But unfortunately, i always have phobia with Google. Because so many was banned before and it not give me a comfort at all.
And i think, if Google still act like that, i think someday there are none will co operate with Google, because many was banned as far as i know. If the publishers ran away, how come there will be any advertisers?
It's not professional they did like that, they must xplain and try to forgive if the fault just for 1 or 3 times and just give warning first.
Their policies are not good for a long term, because so many competitors are out now.
I hope you can succeed with another company, better than with Google. All da best :)