Ask your account manager to speak to the buyer or you speak to the buyer and offer some free gift if possible, that's the only way out. I know this is not the right way to do business but on ebay this is the only way out. You can quote to him the ebay notice for courier delivery times which is "*Sellers are not responsible for service transit time. Transit times are provided by the carrier, excluding weekends and holidays, and may vary with package origin and destination, particularly during peak periods.". This tag line is displayed on every "Shipping and Payments" page which the buyer can check.
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