Citibank — unnecessary amount deduction in my saving account

Address:

No 12 B Street Kuvempu Nagar, new guddadahalli, Mysore Road, 560026

There was a unnecessary deduction in my savings for amount 6280. Mail and sms communication was not be done prior deduction. Suddenly they deducted without any reason. I need refund.
There was no call before the amount deduction and all of sudden amount was debited from my saving account. Its fraud and there is no policy being informed earlier. So i need justice and amount has to refunded with interest.