Airtel — my money was debited from my bank account by online fraud call from airtel customer care using airtel payment wallet.

Following is my case

I have first email to airtel payment wallet customer care email "[protected]@airtelbank.com" for a clarification of a cash back which i have not receive to my airtel wallet as promised in app and after 4 hrs of my email i have receive a phone call from this no [protected] who claim that he is from airet payment wallet team
And he told me that he will add the cash back to my airtel wallet and he also verify my debit card no with last 4 digit no and
By mistake i forward him my airtel app mpin reset sms and after that money were debited from my hdfc bank account. Total debited amount is rs 15k

One qustion i have from this, how the guy know that i have email to airtel customer care? Airtel must have leak my data to suspicious person thats
Why the guy call me.

I have received call and sms from following numbers at the time fraud transaction: [protected], [protected], [protected]