You showed up quick this time. Do you have an e-mail alert set for everytime the word "India" is mentioned.
To the OP (and anyone else who doesn't want to get the ICC), just press the button for International Reservations, you'll get connected to the USA and they'll be happy to help you with your domestic trip.
I don't think I need to justify myself, but I've given up commenting on Indian call center posts. There are just too many xenophobic morons in the world and here on FT and I don't have the time. There are certainly many legitimate complaints that can be made about DL's Indian call center operation. This is hardly one of them. As someone else asked upthread, what kind of idiot gives a CC number to check availability? I would bet dollars to doughnuts that she bought the ticket, changed her mind, and blamed the ever-convenient Indian call center for her own mistake.
If the OP had this experience first-hand, and had a credible posting history, it would be a different situation.