This page contains more information on the sponsored part. Specifically question 4: http://www.flexytalk.com/support/faq/
And in reply of your concerns:
1) First of all: The chat still works on the frist visit, people can still open the Live-Chat with you, even when the sponsored message it shown (above the Live-Chat button)
2) We did quite some investigation on Live-Chat and engagement on the first pageview of a visit is exactly the one that most people don't want to get engaged. It's similar to the situation you enter a store, and with the first step entering the store a salesman start to ask you if he can help you, not the best way to improve customer engagement. However, banners and ads are accepted to be posted in the stores entry door!
And yes, of course there is a way to disable the ads. As explained on our FAQ (http://www.flexytalk.com/support/faq/) it's currently for just $2.75 a month. Don't tell me that isn't a bargain to improve your customer/visitors engagement!