you don't, it's a scam.
It's not
how to do this with escrow?
1. You choose and contact any reliable escrow from this list
https://bitcointalk.org/index.php?topic=2062952.02. You tranfer BTC to escrow.
3. I send email and Bitmain account credentials to you and to escrow.
4. You change all information to yours.
5. You pay money for equipment to Bitmain via bank transfer.
6. You receive miners in October.
7. You send confirmation to escrow.
8. Escrow transfers BTCs to me after you get your antminers.
P.S. new price 1 BTC for all.