The hotel taxi service is nice (flat 650 to airport) but a bit chaotic. If you reserve the taxi for tomorrow morning the night before, for let's say for 9 AM, it means that the reception girl will only call the taxi company at 9 AM, not that the taxi would be there already at 9 AM. So better be at the reception at 08.30 AM and ask then to call a taxi. Since there might be 10 people all waiting to get their taxis. They do not give you any taxi reservation number either, so when one taxi arrives, it will be a fight over that one car.