Banking issue

I have an account with SBI (State Bank of India). An amount was automatically deducted from my account without my knowledge or authorization. This deduction was not expected by me and I did not initiate or approve this payment. I have not received any clear explanation from the bank regarding why this amount was deducted from my account. This is a deficiency in service on the part of the bank. I request the bank to look into this matter, explain the reason for this automatic deduction, and refund the deducted amount to my account at the earliest.