Booked 2 non-cancellable rooms from Hotel Hahn via hotels.com. Day before my stay I was woken up by a call from hotel that my creed card does not work and I must supply another card or card from my friend, otherwise they cancel the rooms. We verified that the card number was correct. I told that the card worked, it worked also during the booking and asked to hold my reservation. There was an e-mail also saying that if I don't supply another card number by mid-day ( I read that at 11:00 ) they cancel my reservations. Another disturbing phone call from hotel at 14:00 on same topic, but with added pressure and insults: "we don't believe you, let's see tomorrow if you come". On arrival, they said that they have full hotel ( that is true, all hotels in Vienna were full ). My rooms had been kept to me. Needed to pay extra breakfast, 12€ and parking 10€.
I can only conclude that Hotel Hahn tried to change customers to get more money from the double rooms that they had reserved for me and my friend ( I reserved 2 singles ). My card still works well - now is 2 days staying in Hotel Hahn. I can only suspect greed. I will avoid this hotel in the future.