Subject: Expedia question

I am trying to book a hotel in Portugal and cannot get a response from the hotel themselves but they are represented on numerous booking agent's sites saying that they are able to "request" a room. Expedia however are keen to take my money right away and ask if my date is flexible. Has anybody had experience with this organisation? Can they be relied on to get a booking for you or give you your money back if they can't get the date I want ( it is not flexible at all).

Thank you, Margaret Melbourne