First, a big welcome to Flyertalk,
nide !!
While I can't help you directly with this particular outfit, I'm sure there are others here that will.
I do have some feedback on a similar site,
www.hotels.com -- they also require that the full payment be charged at time of reservation. This isn't uncommon at cut-rate places.
It always pays to be cuatious when dealing with an unknown party, though, and hopefully someone who has used them can give you some feedback.
Again, welcome to the club.