OP, let's get your problem to a final resolution ASAP. Follow these instructions, very carefully, and it should work out OK by the end of the week.
1. Breathe and relax! Your frustration is warranted -- it's tough to find seats into/out of India for the peak season, and you thought plans were settled when you confirmed your tickets. Going forward, though, you'll have to set the angst aside and focus entirely on the solution.
2. Look at the Delta/Air France/KLM/Korean Air websites and try to identify up to three options offering paid fare options in the same cabin for the origin/destination city pairs you originally ticketed. Jot down the flight schedules, and rank them in your personal order of preference.
3. Compose a fairly short and polite e-mail note to Delta executive Allison Ausband (
[email protected]). Include your confirmation number, a very short rundown of what's happened (sticking to the fact you booked, major schedule change, awful alternative provided), and ask for her team's help in getting you rebooked onto either the flights you've identified, or something similarly acceptable. No rants, no threats, just the facts, sir.
4. With your request now in front of the right people empowered to respond properly, wait for a response, which should be forthcoming quickly.
5. Enjoy your new trip.