Was it the TDF Spectator Guide?
When you list an item with 'free postage', it means you, the seller, is paying the postage.
Your items are listed with Ebay Simple Delivery so Ebay have charged you for a label.
You probably should not have cancelled the order - you may get negative feedback and/or a defect on your account, depending on the reason you chose.
Generally, if you choose 'seller pays' and don't use the label, you have to apply for a refund. I don't know what happens in the event of a cancelled sale but the details of how to apply for a refund are below.
Some categories of lower priced items under 100g are exempt from Simple Delivery. It might be worth having a look and considering if some of your items could be listed in those categories.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)