UPI — regarding the money deducted from my account without my permission

I am kumari ishika having bank account ([protected]) in central bank of india. On 27/09/2017 i got a message from my bank that rs. 5000 is debited from my account but i have not initiated any amount. Then i talked to central bank's customer care executive. He checked my account' s detail and said that the money was deducted by an upi app. Currently i am using the phone pe app but its customer care executive said that this money had not been initiated by them.

So, this is the matter and i want you to help me out with this because i want my money back. Please take some quick steps so that i can get my money back.
Thanks