If you look in Payments you will see where the money has gone.
You have recently listed some items with 3 day auctions, including the shoes you sold.
Every time you choose an upgrade, such as a 3 day auction, you pay a fee. In the case of those items listed as 3 day auctions, it's 35p per item.
So. my guess would be that a chunk of the money taken off your sale was listing fees (optional upgrades) rather than selling fees.
"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)