My son acquired Facebook account charges. Anything I can do?

As stupid as this sounds, my son was playing some Facebook games and accepted some charges in return for some sort of game credit(s). Now the end result isn't too bad- its only $1.60, but is there anything I can do to get rid of the charge? We live in Canada so not only would we have to pay that measly amount but we'd also get an international charge on our card. Plus the whole thing seems a bit ridiculous. Its not like they have billing information or any sort of contact information apart from his name. Any ideas?