Airtel — Issue with charging prepaid Airtel mobile phone number using ICICI NRO Debit card

I am an NRI, USA citizen with OCI card. Few month back I added a prepaid mobile phone number from Mumbai airport. Now I am in USA, and trying to recharge it to keep this number as I need this number for UPI banking. UPI banking is only possible using Indian Mobile phone number currently.

But I am unable to recharge the Airtel prepaid mobile number using my ICICI NRO debit card. It is asking me to use UPI method. But I do not have UPI facility on my ICICI NRO account. Right now I am kind of like egg and chicken issue as I am unable to resolve this. Please let me know how to fix this.