You'll need to cancel that label if bought through eBay link below, then buy another with the correct size and weight.
Or, cancel the label, and take the item to your Post Office to be weighed correctly and correct postage charged. You'll need to then add any correct tracking and manually mark the item as dispatched.
Find your label with this link . It may take 24 hours to appear.
https://www.ebay.co.uk/ship/lmng/labels-history/seller-hub and to the left of the sales record there is a drop down menu under 'Actions' click on that , then click on 'Void Label'.
The refund will take between 5 - 21 days to process.
@simeonvision
