Duplicate item, but seller won't accept messages
I bought something from an eBay seller and it got lost in the mail. I contacted the seller and also asked USPS to investigate. In the meantime, the seller shipped me a replacement item--great customer service, and it arrived in time for Christmas!!!
In the meantime the USPS actually FOUND the lost item and delivered it today. So now I have two of them, and I'd like to return the duplicate to the kind seller (value is about $100.00). However, the seller will not accept messages through eBay, so I can't contact him. The eBay Help Chat was no help, simply saying that "my case has been closed." I have two addresses, one listed on eBay and a (different) return address on the package itself. Should I (pay to) ship it to one of the addresses and cross my fingers, or just keep it?