You can send a combined invoice before the buyer pays if they have already paid you can issue a part refund.
You can issue eBay partial refunds direct from your seller hub:
Find the order in your hub, you’ll see ‘start refund’ on the dropdown menu
Enter the reason you’re processing the refund
Set the amount of money you’re refunding, either by item or by order
Once the right amount is entered, hit ‘send refund’ and you’re done
You’ll then see the amount you refunded show up on the order details.
See how to give a partial refund in eBay managed payments on here:
