If you do not receive a confirmation screen, with a reservation code, and a confirmation email, or in the event you receive an error message - it is highly likely your booking failed, and you would need to try again.
You may see a transaction on your internet banking depending at what point the booking failed, don't worry, this will have been ODEON ring fencing the funds prior to the booking going through. As the booking did not complete, this money will be returned to you by your bank.