We're very sorry this has happened to you but we are hearing of more and more people being ripped off in this way.
From my perspective.....one should NEVER enter into a real estate transaction without first varifying the legitimacy of the party(s) you are dealing with.
We hope you have reported this indisgression to the local authorities.
You can read more about this type of scam here: http://www.fbi.gov/news/stories/2009/july/housingscam_072909/
Again, so, so sorry that this happened to you.
We have had this experience a few times with our 'for sale' listings. The first thing I would suggest is doing a search on Google.com with that address. If it shows that it is for sale, contact the REALTOR that has the listing. We have been able to keep several people from losing their deposit money this way. We also have them call the local police department in the town that the home is located and to flag the ad on Craigslist.
Not all people are this way.
when it sounds too good to be true, it usually is. Sending money to a p.o. box to someone you've never met, for a property you've never seen is just foolish.
Clearly it was a scam, and whether they were "good" and "Christian people" has no bearing.