I just ran into this problem. I do know that EF is going through a change and, if I remember correctly, doing away with the free assignments, while I do not believe this has taken effect yet, seeing how there hasn't been any new post, I think everyone is trying to rack in their free items before they do away with it and some people are taking their times writing their reviews or are just not doing it at all.
I requested 6 different items in about a weeks stretch, because it takes them awhile to let you know if they accept it or decline, before one finally went through. I was constantly on the new items page, on the Eden Link page, and several times on the product search page. Those 6 are the ones that actually went through, I can only imagine how many I actually tired. All I can say from recent experience is, be patient, maybe request something that you wouldn't think is on everyones list to get, you should come across something eventually, hopefully rather sooner than later.