We decided to get the loan from another bank (i.e. they offered us a better deal than the one we got from our current bank) to buy an apartment.
Everything went smoothly until the banker told us via email to send the downpayment to an intern account without any official document.
We feel a bit strange here. Even though we have his emails/contact info but still it is a huge amount and we don't want to have any risk. He said it's a common way to proceed with new customers as we don't have personal accounts there.

What should we do then?
Cheers,