How do I refund postage when 'buyer pays'?

[geomusic]

A buyer ordered two different items for me, one was 'simple delivery' and the other was outside of it due to size. We've agreed with the buyer I should ship the smaller item within the larger package, hence one postage.

As with eBay's simple delivery I didn't receive the funds for the postage, what steps can I follow in order for the buyer to get a refund for the unused Royal Mail label?

Thank you! 

[61stephenuk]

If the buyer paid for the original postage they will be automatically refunded by eBay in around 30 days.

if you were charged for the original postage ie you had free postage on the listing then you need to apply for a refund within 14 days here https://www.ebay.co.uk/claims/simple-delivery/refund/seller and eBay will decide if a refund is due.

[kamcarder]

Sorry - my original question was slightly incorrect.
What I meant was that the buyer paid my requested postage fee when he paid
for the item. I then found the item was too long to post using 'simple
delivery' thus had to pay for and send the oversize item through a separate
courier which ended up costing a lot more than my original quote. Thus I
was hoping to offset this cost (as I couldn't use the 'simple delivery' in
the 1st instance) by receiving the amount the buyer paid.
This might make more sense?
Thank you

[jonatjonatjonat]

Was it the filter?

that was sold buyer pays postage. If you paid for your own alternative postage, that was on you.

if the simple delivery label remains unused a refund will go back to the buyer in 30 days. You won’t be able to claim anything.

[kamcarder]

Hmmm, not really my fault but a lesson learnt. Thanks.