Feedback question on ebay?

So I was selling my game on Ebay and somebody won the auction for 60 dollars. I was pretty disappointed with the price, and the buyer had not payed me yet, so I figured Id sell it to my buddy for 70. I contacted the buyer saying I no longer had it and opened a transaction cancel case thing. This was already a stupid move on my part I realized later, so i got it back from my buddy and sent the buyer a message saying to disregard the cancellation request. But instead he just said that "I still want the item I am the winner buyer and in accordance to eBay I have 4 business days to pay" as if he completely ignored my messages altogether. I explained to him and apologized about it professionally, but he did not message me back. He already payed for the item, and I'm shipping tomorrow. Because he only buys items, he has all 100% feedback, so I don't know if he's a good buyer or not. I'm afraid that he may leave me negative feedback and there's nothing I can do about it. What should I do?