Not sure about the JP miles using HDFC Bank card but there is one more way to earn miles, I am a privilege member of Jet, Air India, Indigo. So whenever you book flights, at that time you have option of adding your privileged member number. So whenever you travel make sure you book flights using privileged number and after you left flight you will recieve miles. To become a privilege member just go to website of Jet or air India and then you will see the option.
'More Seats' – Redeem JPMiles up to last seat** in the 'Select Airlines' – no restriction on award seats availability. Reward Store across Merchandise, gift vouchers, donations – 2500 + options. Fuel Redemption – Select outlets. Hotel Redemption – Domestic & International properties. Answer Source https://www.treasuryprime.com/