If the iPad was listed as 32 gb on eBay and what she sent
you was 16 gb, open a complaint with eBay. If you used
PayPal, you should be protected. If you did a face to face
deal, your protection may have been voided.
Kangaroo, not that this is what you want to hear now, but I and a lot of the others that post here frequently feel pretty nervous about eBay transactions for iOS devices. It seems like always either the device has been stolen, or some issue like this arises. Going forward, if you are looking for a discount, you are far better off to get a refurbished device directly from Apple. I think with where you are now the advice imobl gave is good. How did you pay for the purchase? I suppose the good thing is that at least you have a functioning device.