Apologies if the following has been covered in this thread before—I searched but couldn't find an analogous situation.
I mostly sell clothing on eBay, but the other day I sold a nice piece of pro audio gear. Buyer paid promptly, I shipped it out the next day (Priority with sig. conf.). A few hours after I dropped the package, buyer messages me to say he hopes I haven't shipped the package out yet, he accidentally had his old address on the account, and gave me a new address across the country. Meanwhile his account says he's registered in yet another (third) state.
What's the deal here? A scam? an honest mistake? too early to tell?
Could be either case, really.
You can do a package redirect and basically stop the shipment and redirect it to either the new address (if you trust him), or back to you. You will do it online at the USPS site and will have to go through a few different authorizations to get it done. IIRC it costs about 15 bucks.
If it were me, I would have it sent back to me, have the buyer update his accounts with the correct address and rework the transaction. This will help with the "seller protection".