I've found (counterintuitively) that if you call CCBill support late at night, you'll get Josh or Brandon. I think they are the only two people on most of the time in the late night, and they seem far more knowledgable than most of the day staff. With the exception of really obscure, sales-related stuff, I don't think I've ever had an issue that those guys couldn't answer for me.

If I'm calling during the day, and could choose who to speak to, I'd go for Emmanuel, who seems both amazingly knowledgeable, and incredibly patient and persistent in finding solutions for even the most obscure problems.