I second the CC option. No hassle, and the cc company will help you somewhat if you fall out with the school and your refund is not given, or the school goes bust, or something like that.
Like Trinity said, give the cc company a heads-up call so they can update your record. A large sum of money to a foreign company with which you have no prior record is one of the prime flags that trigger the cc company fraud detection computers. If there's a note in your file saying you called ahead and this is to be expected, they will not call you about it at 4am.
Also make sure there is actually enough credit on your credit card. Simply deposit some additional money on your credit card up front as if you are paying a huge monthly bill (same account numbers and everything). There's nothing more annoying, credit-card wise, than trying to sort out a credit shortage from a foreign country. (Short of losing the cc altogether, that is.) Oh, and a positive balance in your credit card account actually may bring in a tiny bit of interest.