If you look in your Game Q, there is an area up top which reads, "Games I Have Out." If the game still has "At Home" beside it, but you sent it back on the 7th, there is a possibility it was lost in the mail. At this point, you will need to contact GameFly directly and report a shipping problem.

http://www.gamefly.com/activity/report-shipping-problem/
(click the bubble, "GameFly never received my return")