It seems like a luck of the draw situation. Can be 5mins, can be 24hours...
But there are plenty of posts regarding this already, propably more than any other topic on the whole of WHT, it should just be expected from FDC nowadays until they really start shaking up properly.
We had our CC charged twice by them, a CC we hadnt used with them for over 3 months. We thought we'd let them do the refunds rather than chargebacks and see how long it took. 2 weeks in case anyones interested. I guess we'll use the word chargeback a little more fruitfully if it happens again, seems to prick up the ears slightly better than just "we demand a refund".