Start a scam accusation thread (using the recommended format). You might not get your money back but it could prevent some ppl from falling for the same trick.
In the future, only transact with reputable members (you can use a reputable escrow as well) and always ask for a signed message from a non recent staked address of theirs to make sure you are not talking to an impersonator.
In case, you're not familiar with our trust system:
A short introduction to the Trust System
LoyceV's Beginners guide to correct use of the Trust system
Uhm there are reputable members offering escrow services to prevent such scams... ₿ LIST ₿ Bitcointalk's ESCROW providers: Ranking & Blacklist ☠ Avoid Scam ☠
Those people pretended not to be custodians for a long time, and then cheated in their name, which led to me being deceived.