Question about service charges on ticket refunds

I bought a KL ticket at an airport ticket desk for travel 2 hours later, in December. The flight was cancelled owing to weather (the inbound a/c didn't depart owing to WX) and AF (057 stock) refunded me the cost, less a €25 service charge. On querying this, they maintain I have to pay this. Is this normal business practice for AF? I.e. to sell a ticket for a flight they most likely already knew was cancelled, then cancel it, then keep €25 for their efforts?

 

Yep. Sounds like AF/KLM to me!