We have no access to your account so we cannot see why this was charged, and for which item with little information.
This will show you a breakdown of your transaction and show any listing fees / promotion ( ad fees), or postage charged. Be aware, it may apply to items not sold, but still listed.
https://www.ebay.co.uk/sh/fin/transactions
If this doesn't explain the fee charged , contact eBay Customer Services they will explain and fee charged.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open 8 a.m. - 10 p.m. on weekdays
9 a.m. - 6 p.m. on weekends.
Automated agents will be available on chat outside of the above hours.
I recommend contacting CS first thing in the morning as there's more chance of Dublin answering.
@bennalap