Hi there,

Anyone who was scammed should proceed to open up a scam accusation against the account involved. You can do so here

https://bitcointalk.org/index.php?board=83.0

Make sure to include your PM's and any other information you have to prove your case. If it appears to have been a scam a DT member will usually come along and tag OP as their tags are more visible to the community.
Also tag them with your feedback, as some people ( Not enough people) do actually read these.

As a rule of thumb you should always use Escrow, the cost may not seem worth it but then you see a case like this that serves as a reminder.