but how it is possible a hacker using account and staked bitcoin address but the real owner wasn't aware of this but when he took the loan someone created a new account saying it was his account thats hacked.How he got notification within few minutes of taking loan but no notification about any other activity on account.
Have you PM the borrower before sending his loan ? If the hacker didn't change the email address, that could eventually explain why the real owner was aware of this and create a new account in order to prevent a possible scam attempt.
This said, lenders should really do their homework before lending and asking for a signature of an address staked at least 3 months ago, there's too much scam attempts involving hacked accounts. This seems to be the new thing in here now.