They are taking your money without your concent! I book for 10 days in a hostel, UNITEDHOSTEL in barcelona, for 14.17 euros a night and I was charge it for 24.90 because they say it change regarding the day. They just charge me more of what I accepted in my credit card, but also If I were paying day by day in the hostal I will have got a betetr deal! Take care with this transnational, they just take your money legaly and do whatever they want!