Why does various websites support ads that are from verified scam groups?

In fact advertisers are part of the scam. I signed up google adsense in 2008 and in 3 years I made $300. I didnt withdraw any money as I wanted to take it when it reaches $1000. But, few days back they suspended my account and I lost all the money, did not get even a cent. I made an appeal and it was denied saying their experts have decided to not to reinstate my account. I spent nearly $1200 in advertising my blog and from that I made $300 which I lost at last. So, I say Google Adsense itself is a BIG scam. stay away from that. The worst part is they did not tell why I got suspended.