Airtel — prepaid recharge but paytm done postpaid

Address:

Chennai, Tamil Nadu, 603103

I did my prepaid mobile recharge on paytm but they recharged it as postpaid. They gave me the below details.

1) operator reference number: [protected]
2) mobile number: [protected]
3) date and time of transaction: 23-mar-2018

Note: 4 months back i shifted to prepaid from postpaid by paying all the dues.
I checked with both airtel and paytm customer care but there is no proper response from them. Kindly do some needful help to me.

Thanks in advance!