EBay - item was a scam - after purchase?

A while ago i bought a Minecraft gift code off a seller from eBay; all was fine the code worked etc. However, yesterday my minecraft account simply no longer exists. It says that a possibility is that the code was refunded (reset by the buyer of the code, not me, so that it can be used again). So what i think has happened, is that he sells the codes and then when he gets another sale and doesn't have anymore codes he just rests that code and give another buyer that, leaving me without the item i paid for.
I've opened a case on eBay and contacted the buyer, but he's claiming he doesn't know what i'm talking about and hasn't done anything. Obviously not that case; and it doesn't look as though i'm going to be able to do anything about it which i'm really annoyed about. The seller is now just ignoring my messages expecting it all to just go away and get away with it but i refuse to let that happen.
On the eBay case it says that it will be automatically closed tomorrow even though there has been no resolution… I can't find a way on eBay to contact customer support directly because it's just littered with other option like opening a case.
I don't really know what to do, i've opened a case but the seller responded with just a load of **** and so on the case it says the seller has responded with a solution, when they haven't…