HI, I am registered for ebay postage labels but through Australia Post and also have eparcel labels.  I have not used the ebay labels but they must work in a similar way to the eparcel system.  I have recently had to send a couple of return labels for incorrect items.

If there is a return section you should be able to pull up the history for the correct buyer and it will automatically fill out the fields with the information.  Then you send the PDF label to the buyer who prints it off and attaches it to the item. You will be charged the return freight on your account.

With the eparcel system all return labels are around $15 whether it's a $5 freight or $100 freight charge to send, we were lucky as the customer went to get a quote to send a heavy part back which was going to cost them around $130, so this is where we had to do something different, so tried the return label which cost us $15 instead - small price to pay and the customer thinks it's good service.

One tip is to send the email to yourself first so you can see the label, then send it to them from your inbox.  They have the choice to print it at home, or take the consignment number with them and the post office will print it off and attach to item.  It won't be a sticky label, just a normal sheet of paper.

Hope this helps as the ebay labels should work in a similar way, or ask their help department how to do it.

Good luck 🙂