There should be no problem in getting games from ebay (unless the seller specifically says no military bases). The cost is no more than shipping to NY, CA or any other state on either coast.
I ship to military bases all the time, so your fine.
As far as the paypal chargeback goes,If they paid via bank or paypal account transfer then they will pretty much do nothing but tell the buyer tough luck.
As the policy states they don't give a chargeback for defective or damaged goods. (atleast at last check it did)
As I have experienced...