Canara Bank — transaction without my knowledge

Address:

Kanchipuram, Tamil Nadu, 602108

Somebody credited to my account rs 10000 on 14.09.2017. And the bank people not intimate the issue to me. And without my knowledge they debited 10000 rs in my account on16.09.2017. And i meet bank manager she said very cool head office send the mail so they are debit my money. True thing was that money was not mine. But the main thing was without my knowledge why are they debited from my account. And manager said you will face the problem legally.