I can use #UPI again after a month of breakage. Switching linked bank account to ICICI helped, though Federal bank also started working when I switched back to it again from ICICI later.

So not sure what broke in between. I had to add a non mobile number upi id after switching banks each time.

This is the 100% #FreeSoftware way of using #UPI. No need to install any apps and works on everyphone if you have #Airtel sim.

Learn more at https://wiki.fsci.in/NUUP #nuup #ussd