The whole customer care system of HDFC Diners Black or Imperia or whosoever they are called (and whatever is being purported here on in general in social media) is a complete joke. It is in complete contrast to expectations of a reasonable resolution, if at all something like that exists in their system. I am almost in the same boat (though not exactly as mine was a first time HDFC card despite of a decade old relationship) and I had applied to them only because I got a mail from my Alumnus cell that one is eligible for an LTF Black (I incidentally do have the required salary and credentials). Right now I have submitted all my details twice over (don't know what's this card upgrade form - maybe not applicable to me since I never had an HDFC CC) but its been some multiple email exchanges and they still can't confirm if card is LTF despite satisfying the alum criteria. (Today got an email saying that person you submitted details to - we can't find such a RM in the system - please give us her details and branch - incidentally had shared the number with them - they still can't find that lady - don't know whom I gave my degree certificate now 🙂)
After this experience, I feel people should really cut some slack to BoB or Axis for that matter. HDFC is equally complicit and literally sucks at customer care, if not worse off than many others. (And yes, I'll probably wait for that LTF signal from their hallowed portal till eternity maybe)