You have 2 choices.
Either pay for the correct postage and the refund for an unused Simple Delivery label is shown below. Here, you will not be able to add new tracking, and your payout will be held for a minimum of 14 days. If you bought the postage direct from RM / courier online, you'll need to go back there for their refund process.
Or, explain to the buyer the following and with their permission cancel the order, which fully refunds them, and relist the item with the correct postage, for them to buy and pay again. Cancel the order citing, ' Buyer Requests to cancel', this will not affect your seller performance.
If an SD label was initially triggered, the refund goes to whoever paid for that label.
- If you selected 'Buyer pays’ when you created the listing, your buyer will automatically be refunded for any Simple Delivery label that isn’t used after 30 days
- If you selected ‘Seller pays’ and offered free postage on your listing, you'll need to fill out the Request a refund for Simple Delivery form for the label that wasn’t used. Make sure to send your request within 14 days of your item selling.
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