When asking them about it, the reply was
"A listing fee is a one-off, upfront fee that is charged as the listing fee you pay for covers the space your ad occupies while on the site. This fee is applied whether a sale goes through or not and is non-refundable.
It might help to think of us like a newspaper Jarle - when you list an item in a newspaper you pay for the listing whether the item sell or not."
In other words, they don't care wether the sale actually went through, they want their money regardless. Would have been fairer to the seller if they re-listed for free in instances like these. Especially since they take a substantial success fee as well (which a newspaper never would).