Does the (RAL) method when doing your taxes really work and how?

Can anyone tell me if the (RAL) refund anticipation loan really works. For the last three years i've been doing my taxes that way. My refund surpose to be in my account in two days but it never is. I still find myself waiting for atleast two or three weeks. So I want to know what is really the deal with the (RAL). I think my tax preparer is not telling me everything.