Cash Advance fees?

[ihav0frnds]

i used my visa to deposit on ftp. i noticed today that i was charged a cash advance fee of 12 bucks on my statement today...i was a surprised because i've used my card before and didn't remember getting charged for that. i searched on ftp's forum, and the support's response has been telling the user to call the credit card company. how would i argue this though? i can't really say i'm trying to deposit on an online poker site, probably isn't legal in some respect. or is it ftp's fault for changing the way it charges the card?