I sent a package via USPS to an address which I printed through Ebay's link. This is also the listed as the confirmed address on Paypal and only address provided to me. Tracking shows insufficient address. I then called USPS and put tracking info into USPS automated phone system, it says that the item is being returned to me/sender. How do I proceed? Who pays shipping if customer still wants item resent? If customer wishes to cancel is it typical that seller refund costs of item plus shipping? Buyer told me about 2 addresses when I told her that she might be able to intercept package prior to it coming back to me, at the suggestion of RC (RC said that they were able to check that package is still at buyer's PO) and buyer will check on that today.
Buyer told me that I sent the package to buyer's UPS address, not buyer's USPS address. There was no way for me to know about 2 addresses.

