"If a buyer is purchasing multiple items from you, and they haven't already benefited from a postage discount, they can select Request total from seller in their shopping basket. You can then send them an invoice with the new combined costs".
So, for combined postage, BEFORE you go to Checkout, on the top right of the items box, there is a text that reads: "Request total". Click on this to request a new combined postage/discount total.
Send us an ORDER request. We will then amend the order and send you an INVOICE.
If you continue to checkout you will incur postage for all items. WE CAN NOT REFUND POSTAGE AS eBay WILL HAVE TAKEN THEIR POSTAGE COMMISSION.