Never pay down a deposit in a bank account until you have met the seller, seen signed a purchase agreement.
No serious private advertisers ask for a down payment before you meet.
Receiving an email with an in-scanned ID does not mean that you have identified the sender. You do this on the spot, when you sign a purchase agreement.
2 small, 1 floor-standing and 1 main unit - 700€ all together, nobody used them, the apartment was rented fully renovated, nobody lived for 10 years, they just bought it recently, all this is not needed, inventory Klima, +381 62 1988859 Nikola