eBay

I shipped a 3 pound package from 37402 to 14213 via media mail. eBay calculated it at $5.97 and that is what the buyer paid. Now they are getting a notice from USPS that 19.13 is due before delivery. What can be done to remedy this?

I recently had to move out of my house and downsize to an apartment. During which some of my items were placed in storage or donated because it was a quick move. I had 6 listings that I could not fill so I cancelled them and refunded the buyers money...