Hunh ?

So, I’m checking my bank account. See what’s been added and deducted (usually tiny bit added and a lot deducted). Then my eye falls on a strange addition. 2,50 euros from a Desk Services B.V. with the description “croky refund”. Well, people who know me, know I prefer one brand. People who know my very well, even know which taste I’d kill a random family member for. Also, I don’t remember writing any complaint letters to anyone lately.
So, how come ? I really want to know, not so much that I can set this thing straight, but more so on how to exploit this. Free money is always good, y’know.