Um, so yeah this has been bugging me for almost two weeks. I bought a few items from the cash shop the other day in hopes of selling a few of them, but they're all frozen in my inventory. I have purchased many items with GC before and have never encountered this issue until now...
If you used cash from a first time Paypal or credit/debit card purchase then the items will be frozen for seven business days. That does not include weekends or holidays. This is done to prevent fraud. You will need to spend all of the cash down to zero or else any items bought after will also be frozen.