Can you prove that you have been scammed for real by the user DavidXXX ?
Please give us some information regarding the TxId to show us that 0.1BTC transaction were you have been scammed plus, some chat logs.
I'm pretty sure you don't own that amount of BTC a screenshot means nothing you should give us a signed messege from the wallet that contains that amount of BTC.

Also can you give us you'r account name in LBC ?