I dont think google kicked you becouse they didnt wont to pay, its becouse of invalid clicks of your members... or sometimes becouse a lot of people who came to your site clicks ads... so that google algoritm think that you made people doing it, or becouse you have something on your site that tells people to click ads for you to get money.
You see google is cares more about his AdWords clients who pays money to google to show in adsense account, google needs to be sure that visitors of your page who clicks on your ads wont to go to that site not just to make money for you
i think its kinda fer, what would you file like if you payed google 500$ and people are coming to your site not becouse they are intrested to buy somethin from your site... only becouse someone will get money for that.
And about Yahoo ads, i heard that they are good, and pay, but im not sure i can get Yahoo ads on my page, becouse it only pays in USA. right ?!