First you say "Security deposit amount: 6500 EUR or USD" then you say "I, The FuzzStone, will never ask you to transfer any money to me!"
And?

The security deposit happens first, then you meet the buyer? Where does the security deposit go? What's to stop you from running off with the security deposit?
Our people are meeting with the buyer, taking his insurance deposit and leaving him document/receipt for this amount of money.
About "running away". The people I work with have an excellent reputation, they have been working on the OTC-market of Ukraine, Russia and Belarus for many years.