[Resolved]  HDFC Bank — no security of funds and refund

On 1 st june, saturday at 1.30 pm i got a call on my mobile phone. Since i was waiting to get a refund from hyundai, they said they are refund managers from the financial recovery team from the registered office in mumbai. He confirmed my account number and ifsc code and said he will refund the amount via net banking. When i confirmed my account details within a minute i received an otp which withdrew 20, 000 and then consecutively 30, 000. I instantly called up phone banking which took 15 minutes to get in touch with the customer executive and froze my account. I have filed a complaint and have two registered complaint numbers. The fir and the customer dispute form has been sent to mumbai hdfc office but i have not received a revert.
There are concerns that need to be looked into.
1. How was my confidential information leaked? There was not only an otp but customer id and even ipin were regenerated.
2. My debit card details were hacked and my debit card number and cvv number was known.
3. The bank is responsible for my funds and thus how was a beneficiary account been added without verifying the genuine.
There is no compromise from the side not even unknowingly. Please look into this matter and solve my problem on urgent basis.