HDFC Bank — Deduction of Rs. 1999 without any authorization

Rs. 1999 was deduction from my account on 1st jan 2021 midnight without any authorization provided against this transaction, subjected as google pay reward. I was trying to connect with customer care team but not able to do so due to complications to connect through their contacts or sometimes they did not accept calls and disconnected automatically. Kindly reimburse the amount back to my account asap.