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.
Déar customers, don't throw away your tank, it can be repaired and serviced well by we the experienced plumbers at very nice and low funds. We can also make plumbing of the new and used tanks depending on your choice