The requested refund amount exceeds the amount that can be refunded. For help fixing this, see http://sellercentral.amazon.co.uk/gp/help/25281
This error occurs because either the refund amount you are requesting exceeds the amount that can be refunded or the order was Fulfilled by Amazon and cannot be refunded from within your seller account. The ItemPrice or Principal is the amount the buyer paid for a product before shipping and taxes. Common reasons why your requested refund might be rejected include the following:
For example, if a buyer pays £20 for a product (not including shipping and taxes), you can refund up to £20. If you were to refund £15, the buyer's balance is £5. Any future refunds cannot exceed that £5 balance.
To view the current balance for an order, and to determine if it was fulfilled by Amazon, you can search for the order using the Search Orders feature in Seller Central.
To resolve this error, please resubmit your request with a refund amount that is less than or equal to the buyer's current balance for only merchant-fulfilled orders.