Selling fee is payable the moment an item sells. If you cancelled properly then the fee is refunded but it does not remove the original fee you get a credit.
Look in your account for credits and items not yet invoiced, simply your up to date account which will be what shows on your next invoice, if there is no fee credit then you did not do the cancellation properly.
When ebay respond to any case they tell you if a fee has been refunded, I can't see the messages, your invoice or items not yet invoiced but you can.
It does pay to explore to find out what all the links on the ebay pages are for, they are all there for a reason.
