Daily Traveller Pass / International Roaming not working in India

I'm traveling in India, and cannot get any mobile service for my Videotron Daily Traveller Pass. 

I've contacted support, and learned that the only Indian carrier they have an agreement with in-country is Tata Docomo. Despite being in the middle of a large city supposedly in that carrier's territory, I cannot get service, and that carrier does not show up as an available Cellular Network in settings / Cellular / Network Selection.

Has anyone had success using Videotron roaming in India? What's the trick?

iPhone 6S Plus, iOS 12.1.2

The carriers I can see currently are:

IDEA
404 999
CellOne
IND airtel
Vodafone IN
Reliance
IND-JIO

None of those provide service when selected manually.

The last word from Videotron support was: get a local SIM card. Seriously.