This is a really sad situation wether the snakes actually died or he's just trying to scam you. Sorry you had this happen. In my opinion with the info provided, I think he either killed them and knows it's his fault that's why no pics or they are alive and he just thought he could get some cash back. I'm leaning towards he killed them somehow. In this situation, If he gave you pics and there was not obvious damage to the snakes, I would of just gave him the refund because it's a small dollar amount and saves you having to worry about him ruining your reputation. But sinse he was so quick to let it go I think it's obvious he knows it was his fault and your probably best just letting it go. It's never a good thing knowing animals you cared for died but unfortunately it does happen.