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.
Assistance with migration issues in Serbia. Residence permit and permanent residence, opening of sole proprietorship and LLC, assistance in finding housing, nostrification of documents, tutoring of the Serbian language. Free consultations. Payment after work is done.