If you have already sent an invoice to include the delivery cost then send another removing the cahrge (do not hit recalculate) then once the deal is done just use the payment options to mark it as paid. That is just for your own reference so it does not really matter if you mark it paid or not except that ebay may send the buyer a payment reminder now and again.
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It says in this book I am reading that by 2065 80% of women will be overweight.
See what a trendsetter I am?