I've noticed it's easy to get in real currency stuck in purgatory with certain things. As far as I'm concerned it only happens to me with say, Steam and the like, but I'm pretty sure you can't transfer in game cash from say Farmville and the like back out to your wallet.

Like, I can put 20 bucks in my Steam Wallet, but nothing will ever cost 20 bucks. 19.99 or 18.99 or 9.99 or what have you. I'm sure I'll always have some kind of money just stuck in there forever without any way to transfer it out. :p