To add the new tracking number (and mark as dispatched) you still need to generate the original prepaid label. Then go to the More Actions dropdown menu or View Order Details > Postage > Track Package > dropdown arrow and change the tracking. That needs to be done on a desktop browser.
The cost of the original label will be refunded to the buyer automatically in 30 days but there is no way of getting them to cover the cost of what you paid.
