Did they offer any explanation of why they cancelled the sale?
If buyer has been refunded, I doubt that you will get anything from ebay, as they cannot take back from buyer.
Have you contacted buyer, as if you are to be paid, I suspect it will be up to you and buyer to sort out. There is no way through ebay for buyer to pay again, and it would need to be made, using Paypal, Bank Transfer or Cheque.
I may be wrong about ebay refunding you, but CS are well known for telling you what you want to hear but nothing happens.