Everyone saying "OP should have used escrow" but how the fuck an escrow will be a good choice for transactions that involve accounts? If I'm not wrong, OP is trying to buy some verified account. What if the seller sells the account and changes the details later? An escrow won't be helpful in this case and that's why forum's reputed escrows avoid account trades.
I'd say that escrow is always better than no escrow. There is always a risk even with escrow, especially when you are dealing with reversible forms of online goods like this which can be easily retrieved after the ownership is transferred and the escrow is released, but using escrow does at least reduces the risk that the person just takes the money and exit scams like what happened here.
But you're right, this is why account sales whether for accounts on forum or off forum is generally a bad idea.
OP, this is why you shouldn't trust someone solely based on their ranks. The person in question had no reputation on the forum. Bitcointalk accounts can be easily bought and sold, and ranks don't tell the full story. Since there is another outstanding scam accusation against the same user, I would seriously doubt your chances of getting your funds back. In the future, be more careful. Do research about the user's reputation you're trying to deal with, before commencing.