How do I cancel a Royal Mail postage label?

[narkey2000]

Is there a way to cancel a Royal Mail postage label as a seller? I've tried following the steps in Seller Hub to cancel the label but it's saying the label can't be cancelled. I ordered it in error, just clicked a button to get buyers address and it said I'd bought a label! The item will go for letter post so I've paid way more than I needed to annoyingly! 

[**peaseblossom**]

If it's Simple Delivery the label cannot be cancelled but you can cancel/refund the transaction and relist with correct postage for the buyer to buy and pay again.    But you have to use the label supplied by ebay unless you manage to opt out of SD during the listing process.   With SD you don't see the buyer's address before getting the label.