Is there an option where one does not want to pay by credit card but still wants to avail pre-purchase tariffs?
Yes. You may contact the reservation agent, deposit payment in as per one of the options and then have the reservation agent make reservations for you. Here the only issue is that in the event of rooms getting booked online by someone else in the mean while, reservation agent will be unable to do the reservations and you will have to opt for another option and will have to pay or will receive the difference amount in case its applicable.