I've noticed the same decline in the last four months with what looks like the same sponsor. My unique to free ratio doubled and is on track to tripling. This week I am nearly 500:1 unique to free with them.
I'm interested in alternatives because I refuse to keep a sponsor up when they get this bad. There are some old ones I will be trying again but am on the lookout for new sponsors too who have customizable iframes which show profile pictures. Most important: NO GAMES! Just give me what is due to me and I will keep you up. It's not hard!