In the case of UPI, customers should report the fraud to both their bank and the payment company whether it is Google Pay, Paytm, PhonePe or others. In case of a payment fraud on an e-commerce website, a PoS device or an ATM, customers should file the complaint with the card issuing bank.
A complaint shall be first raised with the relevant TPAP in respect to all UPI related grievances / complaints of the end-user customers on-boarded by the PSP Bank / TPAP (if the UPI transaction is made through TPAP app). In case the complaint / grievance remains unresolved, the next level for escalation will be the PSP Bank, followed by the bank (where the end-user customer maintains its account) and NPCI, in the same order. After exercising these options, the end-user customer can approach the Banking Ombudsman and / or the Ombudsman for Digital Complaints, as the case may be.
https://www.npci.org.in/get-in-touch