Seller sold me S4 but won't deactivate license

Recently purchased an S4 MK2 advertised as brand new (other) on eBay. Received the hardware, hooked it up, but once I get to activation, NI is saying that the hardware is already registered to another user. I contacted the seller, asking him to de-activate his license. He says he will but has to fax the form yada yada. Weeks pass and it's still not de-activated - at this point I've tried to register about 15 times. I contact NI support and they say that unless the seller contacts them, they can't help me activate the hardware, regardless of whether or not I have all the pertinent info and proof of purchase. The seller is ignoring my messages.

So, am I screwed here? I would have just purchased brand new equipment if I knew I had to purchase software on top of the actual hardware.

 

I think that all you can do is raise an eBay dispute, including if you can confirmation from NI that the seller had registered the hardware and therefore it was not "brand new".