Adjustment on final valuation fee on postage? How to claim?

[13*gem]

I sold multiples on a listing which offered a flat rate postage.  However on check out the postage got multiplied (my bad - mistake in setting out the listing....).  The buyer paid without asking for a combined invoice.  I have refunded the overpaid postage.  Just wanting to know how I can claim a correction to the final valuation fee.  This is only a couple of cents, but wanting to learn how to process this for future reference and when the amount matters.   Thanks.

[kopenhagen5]

ebay want sellers to educate their buyers to wait for an invoice before paying.

When it was first introduced the fee was calculated on sale price not adjusted invoice amount and ebay were asking members to contact ebay for a credit.

There hasn't been much talk of this one of recent so don't know if the system has improved.

Even so I would imagine it would still be the fee on the invoice amount, incorrect or not and no way of recouping difference unless ebay was contacted.

Once again I am not sure if refunding payment, then re-issuing invoice would adjust in fees, I don't think so.

Not yet anyway. Upon implementation of the new fees on postage, accounting for many scenarios was just not included.