I accidentally booked a hotel on United website. I tried to cancel within seconds, but was unsuccessful. I made multiple calls to hotel, United Customer Care, Website support (radial button to cancel was not an option - "website down"), Chase to cancel. No one could help me, because they couldn't see reservation. However, hotel did assure me that my card was not charged. Chase United Explorer would not reverse charges. What or who could I have called - should I encounter this situation again?