That’s frustrating, especially when you saw it included at booking.
With IndiGo, meals are usually tied to the PNR and show up under “SSR” or services on the boarding pass or in their device. If it’s not there, cabin crew generally won’t hand one out because catering is loaded based on those counts.
A few possibilities:
The fare included a meal, but it wasn’t actually selected (some fares require you to choose it).
There was a system glitch and the SSR didn’t attach properly.
It was a codeshare or third party booking issue.
What you can do now:
Check your original booking confirmation email carefully. Does it explicitly list a meal under add ons or inclusions?
If yes, file a complaint through IndiGo’s website and attach screenshots.
Ask for a refund of the meal portion if it was clearly included.
Onboard is hard to fix if it’s not in their system, but post flight refunds for missed prepaid meals are pretty common if you have proof.