Last week I booked 3 nights at the new Courtyard by Marriott in Singapore - but yesterday I noticed that while other hotels and airlines had charged for my travels, the advance purchase from Courtyard by Marriott had not been deducted from my account (not even in pending transactions).

I contacted the hotel directly by email and asked what the issue was, and I got a reply saying that the reservations team tried to deduct my account but was declined.

First off, should the hotel not have contacted me immediately to inform me of this, or was I supposed to only find out upon landing in Singapore?
Secondly, it seems there is smallprint (not made clear during the booking process) that prepayment rates (advance purchase) made online with Courtyard, and presumably the whole Marriott group(?) can only be made with credit cards - not debit cards.

Has anyone heard of this smallprint before? I am pretty well travelled and have stayed in better hotels than this one and have not came across this smallprint before, so I suspect this is why my 'payment' was declined, simply because I am not using the correct card.

Presumably now my booking is void unless I want to change to a 'pay at the hotel' rate which is of course much more expensive.
The hotel is contacting me later on today with more info, although if they're hoping for a credit card then I don't have one!