Debit Cards

Both banks offer competitive corporate salary accounts that come with premium benefits. ICICI has good online banking service and customer care service. HDFC offers high interest rates on savings. 
So while selecting the premium card for yourself, choose the card that gives you good rewards, a daily cash withdrawal limit, travel benefits, and a good cashback facility.
Both cards offer excellent services. So choose the card that fits according to your spending habits.

There might be a technical issue with the PNB app at that moment. Try to upgrade your card at a later time. If you are still not able to upgrade your card, it's better to visit your PNB branch and tell the staff to upgrade your Classic Debit Card to a PNB Platinum Debit Card and they will upgrade your card.

Both cards offer verity of benefits and have almost the same features. But I would suggest the HDFC Platinum Debit Card to you. As this card gives you more rewards points and have high transaction limits. This is a perfect card for you.

You seem right as Platinum International debit card works for that. I have done the same and have the same experience. All you should know is about charges; i.e. cost may include Issuance fee, annual maintenance fee etc. Also for overseas cash withdrawals, they charge Rs 100 with 3.5% + GST of the transaction amount.

That's very strange. There have also been reports of surcharges applied to debit card purchases of fuel. It's important to review the Axis Bank's conditions. Have a word with customer care and ask for the clarification or a refund.