Following point can been seen on their Platinum Debit card page:
"Credit Card BillPay transactions made through Debit Card will NOT earn any CashBack points with immediate effect as this is not an eligible category for the same"
HDFC has added the following comment on Platinum DC Page:
"Credit Card BillPay transactions made through Debit Card will NOT earn any CashBack points with immediate effect as this is not an eligible category for the same."
Updates:
As per the members reports the working portals are SBI Unipay website, Jio Finance app, Airtel Thanks app and Canara Setu website. Please use as per your own discretion.