http://www.ripoffreport.com
Have you seen this site? You can search for credit card processors/adult sites and see the consumer complaints against them. I searched for "ccbill", "ibill", "porn", "sex", "adult" and got some interesting results.
here is the search form:
http://www.ripoffreport.com/search.asp
I hope rebilling customers after they have cancelled isn't done intentionally.