If you think it was definitely UPS at fault then I would work with the seller to get the warranty claim but also send it back. As a pretty regular Ebay seller I would have offered free returns, and then on getting it back opened and damaged I would do a 50% refund, so don't be surprised if he does that (it is a pretty new update, where free returns allows partial refunds) but it will protect the seller so he won't lose money on the transaction. Some buyers get really upset but I have never had a customer fail to get their money back from Ebay and had like 7 laptops partially refunded in the past month alone...The real purpose seems to be to allow Ebay to monitor IP addresses, bank accounts, and other buyer information and then associate that information across multiple accounts so they can block scammers, while hoping to boost sales with free returns. If the seller didn't offer free returns just return it as damaged and don't feel bad, he should have switched to free returns if he wanted to protect himself.
Yes, i you per this on an iPhone