Update - Someone from HDFC called today, said that they listened to the recording and confirmed that I was misinformed. The call was on 29/08, so he asked why I paid my dues separately for last statement after the call but didn't for the next month. I explained to him that I was adding card on cred and as such I just paid for the card to check whether it was added properly on not. For the next statement I was looking to buy things with Millennia card and as such I deposited more than the total amount to Millennia card itself. Since I was under the impression that it would be enough, I didn't pay for the other card separately. The executive kinda got stuck on this point, that how come I paid one statement correctly even after the call and but missed the next one. We talked over this for 3-4 minutes straight me trying to explain and he going in circles yes sir, I understand but it doesn't make sense to me how you paid one time and didn't pay next time. Finally after doing this 3-4 times and me explaining him point by point and with details of the payment he said fine, he would inform the concerned team. Tbh by the looks of it, I would need to take it up to the RBI.