No SD refund on a cancellation?

se2020

I've only just noticed this,

Buyer purchased an item and paid.
The postage amount was deducted from the sales price (was listed with free postage)
Buyer then said they had made a mistake so I cancelled the sale using 'Buyer asked to cancel '

The refund taken from me was the full sales price but the postage amount has not been credited to my balance even though I had not clicked the link to create the lable. 

I requested a refund, none of the reasons applied so I clicked 'other' and entered "order cancelled by Buyer before postage label created " in the text box.

I have just had an email to say my request for a refund has been denied as I have not provided an alternative tracking number that shows the item was delivered!!

I've also looked through my sales history and there are 2 other sales where this has happened, ie. I've been charged for the postage label at the point of sale, Buyer has cancelled   I've not had a credit for the unused label.  Both of those are more than 14 days ago so I can't manually claim for a refund but I think it's probably pointless using the online claim form for this issue..

Just wanted to make others aware of the issue not that I know what to do about it!