You need to try harder. :-)
A refund form is here:
https://personal.help.royalmail.com/...rms/fee_refund
Alternatively try this:
- Go to the Royal Mail app Homepage.
- Click on "Help ?" on the bottom bar of the page.
- Click on "How do I submit a claim".
- Click on the first red "Claim Form" button.
- Scroll down to "Claiming for delayed items" then click on "Special Delivery Items".
I'm sure that a claim has to be initiated within 14 days of the delayed RMSD package and only by the person who sent the package.